updating some of my favorite BtVS/AtS crossovers of the non-SG1 persuasion
originally posted 11/16/11, and last updated on 5/30/18
Warning: This is my personal list of reminders, for the purposes of re-reading and recommending BtVS fics that are NOT crossed with SG1 or SGA (see my recently updated list of SG1-related crossover fanfic faves and recs for BtVS/SG1 crossovers, as well as my list of SG1 crossover fics unrelated to BtVS and list of crossover fics unrelated to BtVS or SG1), so there may well be spoilers in A FEW of the descriptions below. I'd advise you to skip reading the descriptions and just click on the links to check the stories out for yourself, if you're extremely concerned about plot or relationship spoilers. Otherwise, please enjoy this very incomplete listing of some of the stories I've enjoyed reading and re-reading over the years!
* * * * *
Batman (and/or DC Universe in general):
"JLA and the Slayers" SERIES by Nycorson (post-"Chosen" Xander finds himself forcibly sidelined by Willow and Buffy, but accepts a job offer to train newly awakening Slayers in the DC/Justice League universe, where they've never had Slayers before): http://www.tthfanfic.org/Series-2233
"Financial Supporters" by Sheilynn (Buffy/Bruce; delightful one-shot): http://www.tthfanfic.org/Story-5690-3/Sheilynn+Christmas+Falalalala-lidays.htm
"Bat Signals and Stakes" SERIES by Damia (Dawn/Dick Grayson): http://www.tthfanfic.org/Series-2367
"The Joyce Summers School for Gifted Girls" by MaeveBran (Buffy/Bruce; technically unfinished at 12 chapters, but ends in a good place): http://www.tthfanfic.org/Story-17066/MaeveBran+The+Joyce+Summers+School+for+Gifted+Girls.htm
"The Wrong Girl" by FaithUnbreakable (very DARK Buffy/Bruce fic, with coda linked at the bottom of the story; set post-The Dark Knight): http://www.tthfanfic.org/Story-18022/FaithUnbreakable+Wrong+Girl.htm
(WIP) "Gotham Slayer" by CousinMary (epic-length story of what happens when Buffy and Dawn move to Gotham after Sunnydale's destruction, where Buffy finds herself accidentally adopting a masked vigilante persona and quarreling with Batman, neither knowing that they're also dating one another as Bruce and Buffy; not updated since 2010, but still worth reading): http://www.tthfanfic.org/Story-18314/CousinMary+Gotham+Slayer.htm
(WIP) "In Darkest Night" by DWDuck (not updated since early 2011, but a wonderful 6-chapter AU in which newly ensouled Spike, still in Africa, gets chosen as successor to a dying Green Lantern and comes back to Sunnydale able to be of far more assistance to Buffy than anyone expected): https://www.fanfiction.net/s/6533732/1/In-Darkest-Night
Battlestar Galactica:
"A Bug on the Cosmic Windscreen" by missmurchison (Spike gets picked up by a Raptor and finds ways to make himself useful among the Colonials): http://www.tthfanfic.org/Story-8436/missmurchison+A+Bug+on+the+Cosmic+Windscreen.htm
Big Bang Theory:
"It's Only the End of the World" SERIES by droidgirl (Sheldon/Penny; Penny's previous encounters with 'Anne' the Vampire Slayer and with Gunn and his vampire-hunting crew prepare her somewhat for the hellish conditions in LA at the end of the AtS finale "Not Fade Away," and she and Sheldon join forces with Spike and friends to survive; HIGHLY recommended!): http://www.tthfanfic.org/Series-1986
"The Sublet Sublimation" by grundy (short but very cute; Dawn Summers sublets Leonard's room in Apartment 4A and has an 'interesting' time getting to know her new flatmate): http://www.tthfanfic.org/Story-29374/grundy+The+Sublet+Sublimation.htm
"The Undead Entropy Anomaly" by grundy (short but sweet; Dr. Dawn Summers sublets Leonard's room in Apartment 4A, but has to call Penny for reinforcements when Sheldon has an extreme reaction to learning that vampires are real): http://www.tthfanfic.org/Story-28117/grundy+The+Undead+Entropy+Anomaly.htm
"It's All About *Who* Says It" by mmooch (delightful short-fic; Sheldon/Buffy!): http://www.tthfanfic.org/Story-24180/mmooch+It+s+All+About+Who+Says+It.htm
"The Dawn Conundrum" by mmooch (3rd and final story in a series in which Buffy's allowed to R.I.P. after season 5, but can easily be read by itself; Dawn goes to live with cousin Penny in Pasadena after Buffy's funeral, rather than staying in Sunnydale, and this short-fic shows Dawn's reaction to learning about the stunt with the can-opener in the Arctic): http://www.tthfanfic.org/Story-24777/mmooch+The+Dawn+Conundrum.htm
"The Reality-Theory Convergence" by DianeCastle (Penny's new job as office manager for the LA branch of Slayers Inc. provides almost as much entertainment and satisfaction as having Buffy and some mini-Slayers as Sheldon's new upstairs neighbors): http://www.tthfanfic.org/Story-28227/DianeCastle+The+Reality-Theory+Convergence.htm
Bolo!:
"It's Not the Size of the Dog in the Fight" by Samarkand (lewd, crude, and occasionally hilarious; Xander becomes a miniature Bolo for Halloween): http://www.tthfanfic.org/Story-19725/Samarkand+It+Ain+t+The+Size+Of+The+Dog+In+The+Fight.htm
"Of the Line" by ghostwhowalks (Chloe, a Bolo with a soul, is called to be a Slayer only 1200 years after her sister Potentials were activated in "Chosen"): http://www.tthfanfic.org/Story-9996-3/ghostwhowalks+Of+The+Line.htm (first 4 chapters make a complete story, with the rest an unfinished epilogue venturing into multiple crossovers)
Chronicles of Narnia:
"To the Ground" by Faithunbreakable (Buffy gets tossed from universe to universe, spending lifetime after lifetime in unwilling service to the higher powers, until she falls into Aslan's domain and is tasked with protecting Prince Caspian . . . and manages to connect with King Peter along the way): http://www.tthfanfic.org/Story-20263/FaithUnbreakable+To+The+Ground.htm
Dark Angel:
"Family Ties" SERIES by kerrykhat (Buffy and Faith discover that their genes were used to make Max and her siblings, and they're not ones to leave their kids in the lurch, no matter how unusual or unwilling their conception may've been): http://www.tthfanfic.org/Series-1964
(WIP) "My Life for You" SERIES by Charlotte/
dharkapparition [formerly dharkcharlotte] (Buffy/Ben): http://www.tthfanfic.org/Series-882
Dexter:
"The Wolves" by FaithUnbreakable (Buffy/Dexter, pre-series for Dexter and post season 2 for BtVS): http://www.tthfanfic.org/Story-17697/FaithUnbreakable+The+Wolves.htm
"Predatory Connections" by Litgal (Spike/Dexter one-shot; very bloody, but affecting): http://www.tthfanfic.org/Story-16203/litgal+Predatory+Connections.htm
Doc Savage:
"Older and More Savage Times" SERIES by batzulger (Faith/Clark Savage IV; Slayer and part-time U.S. Marshal Faith finds an unexpected ally against supernatural threats in the latest generation of the Savage family): http://www.tthfanfic.org/Series-3058
"Nacht" SERIES by batzulger (Kennedy finds herself dumped into another universe in 1930s New York City, and invents a "Shadow"-like masked alter-ego for fighting crime and Nazis, with the eventual assistance of extraordinary people like Pat Savage and Nicola Tesla): http://www.tthfanfic.org/Series-2904
Doctor Who/Torchwood:
"Who's the Doctor?" SERIES by missmurchison (series of brief stories, starting with an AU and much more Spuffy friendly version of "As You Were" featuring the 10th Doctor and proceeding with further AU season 6 encounters with the 9th, 4th, and 7th Doctors and Dawn's ongoing friendship with the TARDIS; all 4 stories are also available on LJ at various locations): http://www.tthfanfic.org/Series-2847
"Who's the Doctor?": http://missmurchison.livejournal.com/389657.html#cutid1
"Dawn of the Doctor" (Dawn helps the newly regenerated 9th Doctor): http://missmurchison.livejournal.com/522536.html
"Where's the Doctor?" (12 brief chapters; 4th Doctor and Leela): http://seasonal-spuffy.livejournal.com/295675.html
"Buffy and the Dalek Slayers" (9 chapters; 7th Doctor and Ace): http://seasonal-spuffy.livejournal.com/424280.html (http://seasonal-spuffy.livejournal.com/tag/creator%3A%20missmurchison)
"My Immortal" SERIES by Elisi (Buffy/Jack, and later Buffy/Spike): http://www.tthfanfic.org/Series-1606
"The Doctor's Faith" SERIES by DWDuck (Faith/Ten; At least one of the Powers recognizes that Buffy needs help against the First and so arranges to set the Doctor on the case; starts just post-season 4 for the new DW and late season 7 for BtVS, and goes AU from there, with a (so far) final installment being a 'Smallville'/'Torchwood' cross): http://www.tthfanfic.org/Series-3076, or see
1) https://www.fanfiction.net/s/6363098/1/The-Doctor-s-Faith-Healing,
2) https://www.fanfiction.net/s/6433684/1/The-Angel-Has-the-Phone-Box,
3) https://www.fanfiction.net/s/6765535/1/The-Angel-s-Voice,
4) https://www.fanfiction.net/s/6608411/1/The-Doctors-and-the-Keys [unfinished since 2014], and
5) https://www.fanfiction.net/s/6055853/1/Captain-Jack-Comes-to-Smallville
"Impossible Things" SERIES by MoragMacPherson (Buffy/10th Doctor; a weeping angel sends Buffy to an alternate version of 1913, where she ends up scrubbing floors along side of Martha at a boys' school and piquing the interest of Prof. John Smith): 1) http://www.tthfanfic.org/Story-17978/MoragMacPherson+Impossible+Things.htm; 2) http://www.tthfanfic.org/Story-18638/MoragMacPherson+Sitting+Waiting+Wishing.htm
"Golden Threads" SERIES by Jaded (Jack/Ianto/Dawn; epic story of Dawn, the Scoobies, and their whole extended family becoming closely involved with Torchwood 3 and the Doctor): http://www.tthfanfic.org/Series-2155
(WIP) "Tick, Tock, One Little Clock" by Doctorsgirl (eventual Buffy/Doctor; the old pocket watch Buffy adds to her Halloween 'lady' costume is from a previously used chameleon arch transformation and funnels all the energy of the Janus spell and the Hellmouth rift into Buffy's permanent transformation, erasing her existence from the minds of her friends and family on earth; calling herself 'The Slayer', she and her companions do a lot of evil-vanquishing and running around the universe, until they find the 10th regeneration of The Doctor, no longer the last of the Time Lords; incomplete, but still well worth re-reading, as Buffy and her TARDIS crew join some of the Doctor's adventures in season four): http://www.tthfanfic.org/Story-21501/Doctorsgirl+Tick+Tock+One+little+clock.htm
"Ghost Story" by Mhalachai (Dawn meets Captain Jack): http://www.tthfanfic.org/Story-15762/Mhalachai+Ghost+Story.htm
Farscape:
"From Heaven and Hell" by Tassos (while searching for Dargo's kidnapped son, the crew of Moya find the trail leads straight through a wormhole to Los Angeles on Crichton's home planet, and the PTB send Angel to help them out, a few episodes shy of the AtS season 1 finale): http://www.tthfanfic.org/Story-5467/Tassos+From+Heaven+and+Hell.htm
"When Good Spells Go Bad" by Kennie (Willow accidentally ends up on Moya; Willow-Crichton friendship, with Crichton/Aeryn romance unthreatened): http://www.tthfanfic.org/Story-18455/Kennie+When+Good+Spells+Go+Bad.htm
Firefly:
"Well That Went Well" by MissE/ObscureEnough (while trying to hide Dawn from Glory, Dawn and her two protectors -- Xander and Faith -- end up spending time on 'Serenity' before, during, and just after the events of the movie): http://www.tthfanfic.org/Story-23376/MissE+Well+That+Went+Well.htm, or http://misse.livejournal.com/33065.html
"Collecting Xander" by Kei (post-BDM; River/Mal, eventual Zoe/Xander): http://www.tthfanfic.org/Story-15967/Kei+Collecting+Xander.htm
"Cookie Crumbs of Fate" by Crunchysunrises (Buffy is drawn forward through time, from before the start of season 4, to come to the aid of River on Serenity, and hopefully also the other children of the Academy, eventually): http://www.tthfanfic.org/Story-29296/Crunchysunrises+Cookie+Crumbs+of+Fate.htm
"I'm Here to Tell You About My Dream" by Kaela (Buffy asks Inara and Jayne to help her finally end her life): http://www.tthfanfic.org/Story-23756/kaela+I+m+here+to+tell+you+about+my+dream.htm
"Leaves on the Wind: 'Firefly' and 'Serenity' one-shots" SERIES by JediButtercup: http://www.tthfanfic.org/Series-2970
"All Made Up" by JediButtercup (The Wolf, Ram, and Hart are still messing about, and they seem to have targeted Mal's crew for particular harasshment; 4 short inter-related AtS/Firefly crossover stories): http://www.tthfanfic.org/Story-27811/jedibuttercup+All+Made+Up.htm or http://archiveofourown.org/series/9243
"Sidle Up and Smile" SERIES by JediButtercup (Buffy and Faith haven't aged since Willow's spell, and Buffy is Mal's mother): http://www.tthfanfic.org/Series-1047 or http://archiveofourown.org/series/1446
"Colors" by anaross (post BDM, Spike/Zoe friendship; either six months or 500 years after the battle in the alley behind the Hyperion, Spike finds himself stranded alone in the future, hoping somehow that Serenity and its crew will be able to help him find his way back to Buffy, while he helps River cope with her confused Slayer line memories): https://www.livejournal.com/tools/memories.bml?user=anaross&keyword=Colors&filter=all
"Our Mrs. Cobb" by Sevangel (River/Jayne and Willow/Mal/Inara): http://www.tthfanfic.org/Story-8457/sevangel+Our+Mrs+Cobb.htm
"Slayers in Space" by Sevangel (River/Jayne and Faith/Mal): http://www.tthfanfic.org/Story-7824/sevangel+Slayers+in+Space.htm
"Finding Home" by Sweetdoggie (Buffy/Jayne -- 10K word one-shot): http://www.tthfanfic.org/Story-15946/Sweetdoggie+Finding+Home.htm
"Finding My Serenity" by Cjsplace (Buffy/Mal, going AU with Buffy leaving her home dimension right after slicing up Caleb): http://www.tthfanfic.org/Story-9863/cjsplace+Finding+My+Serenity.htm
"Starting from Scratch" by agilebrit (post-NFA, Spike and Illyria jump a portal to 500 years in the future and end up meeting River when they take passage on 'Serenity'; short-ish 5K words): http://www.tthfanfic.org/Story-12185/agilebrit+Starting+from+Scratch.htm
"Another Day, Another Apocalypse" by agilebrit (a.k.a. 'babies stole my dingo') -- post NFA, Fred, Spike, Angel, AND Illyria end up on pre-BDM Serenity, in time to activate River and Zoe as slayers and fight WFH's new attempt to open a hellmouth (Jayne/Illyria!): https://www.fanfiction.net/s/2974220/1/Another-Day-Another-Apocalypse
"The Very Small Girl and the Monster" by Snickfic (Spike & River): http://archiveofourown.org/works/158455
"Many Possible Vampire Husbands of Buffy Summers" by hellbells (multi-cross, desperately in need of proof-reading like all of this author's work; Buffy becomes immortal, marries Damon Salvatore, and together they end up aiding River during "Objects in Space"): http://www.tthfanfic.org/Story-27869/hellbells+Many+possible+vampire+husbands+of+Buffy+Summer.htm
(WIP) "Goodnight Daughters" SERIES by Syriope (not updated since 2009; Buffy and River as Academy escapees): http://www.tthfanfic.org/Series-974
(WIP) "From Here to Serenity" by bastardsnow (not updated since 2007, but worth re-reading anyway; Xander and Willow hop dimensions and jump five hundred years into the future in an attempt to find Buffy after "The Gift", and they end up almost hijacking Serenity in order to get to long-lost "Earth that was", where Buffy turns out to have landed): http://www.tthfanfic.org/Story-7081/bastardsnow+From+Here+to+Serenity.htm (also at http://www.fanfiction.net/s/2703205/1/From-Here-to-Serenity or http://bastardsnow.livejournal.com/tag/fhts)
(WIP) "Book's Legacy" by JediButtercup (not updated since August 2010): http://www.tthfanfic.org/Story-7761/jedibuttercup+Book+s+Legacy.htm
(WIP) "Carving Out a Future" by Dreamfall (Xander gets magically frozen by Willow until they can find a way to save his life, which doesn't happen until the 26th century, long after everyone and everything Xander knows is gone, leaving a formerly one-eyed carpenter displaced in time and travelling the 'verse with the pre-BDM crew of Serenity; formerly stalled at 51 chapters on TtH since 2010, but updated to 54 chapters in 2018): http://www.tthfanfic.org/Story-7832/dreamfall+Carving+Out+a+Future.htm (but see also chapter 52 posted to LJ in 2011, ch. 53 in 2014, and ch. 54 & 55 in 2016: http://dreamfall-nnwm.livejournal.com/23561.html)
Galaxy Quest:
"Questing Around the Galaxy" SERIES by Lucinda (Cordelia gets a recurring role on the revived SF series 'Galaxy Quest', just in time for the worlds of aliens and demons to intersect -- Cordy/Jason Nesmith, Willow/Alex Dane, Angel/Gwen DeMarco, Fred Kwan/Laliari): http://www.tthfanfic.org/Series-178
Gargoyles:
"Defender of the Night" by MMcGregor (Xander dresses as Goliath for Halloween, and it sticks): http://www.tthfanfic.org/Story-6269/MMcGregor+Defender+of+the+Night.htm
"BtVS/Gargoyles" SERIES by Aesop (includes ST:TNG crossover in final installment of the 8-story series): http://www.tthfanfic.org/Series-156
"Heroes" by LMouse (one-shot with Buffy stuck in snowbound New York and working/semi-flirting with Brooklyn in order to take down a troublesome vamp; set before Buffy finds out that Spike's back and stuck at W&H: minor cross with the Ron Perlman Beauty and the Beast series and a few other franchises, as well): http://www.tthfanfic.org/Story-4717/LMouse+Heroes.htm
Gilmore Girls:
"A Schism in Stars Hollow" by Litmouse (Part of the "Father Goose" series, but can be read on its own; the Scoobies and significant others come to Stars Hollow for a convention of Xander-and-Faith impersonators, but discover there's more than just quirkiness afoot): http://www.tthfanfic.org/Story-10926/litmouse+A+Schism+in+Stars+Hollow+A+Father+Goose+Digression.htm
"In the Key of Major Finn" by Mhalachai (post-series for both BtVS and GG, Lorelai didn't get back together with Luke and Riley is a widower whose services have been made redundant by the multitude of Slayers, so . . .): http://www.tthfanfic.org/Story-12190/Mhalachai+In+The+Key+of+Major+Finn.htm
"Life Saver" by Belgintei (season 1 for GG and last half of season 7 for BtVS; Luke Danes has to tell 'former' Potential Lorelai Gilmore and current Potential Rory about the supernatural and evacuate them to Sunnydale to escape the Bringers, and the addition of these GG characters smooths out some of the emotional rough patches for Buffy and others in those final days; darker sequel "Life Saver II" has been stalled at an early point in the narrative since 2007, but main story is finished): http://www.tthfanfic.org/Story-7629/belgintei+Life+Saver.htm and http://www.tthfanfic.org/Story-9222/belgintei+Life+Saver+II.htm
Glee:
"Catch a Falling Star" by toots (Rachel leaves Lima to begin her Slayer training, and the Glee crew realize how much they miss her after she's gone): http://www.tthfanfic.org/Story-22113/toots+Catch+a+Falling+Star.htm
Good Eats:
"Good Slaying" by Justaguy (Buffy and Willow evaluate a new potential teacher with a unique approach to educating mini-Slayers in this delightful little ficlet): http://www.tthfanfic.org/Story-6736/justaguy+Good+Slaying.htm
Grimm:
"Not a Dream, Fairy Tale, or Imaginary Story" by Batzulger (primarily a "Grimm"/BtVS crossover epic, with a secondary cross with "The Sentinel" in the form of a now Guide-less Jim Ellison, and a minor cross with "Fringe"; many years post-Chosen, Buffy and Dawn move from Cleveland to Portland, where Dawn teaches at a local university while Buffy works as a homicide detective, coming to terms with the heretofore largely unknown world of Wesen and Grimms and partnering with another recent transfer from Cascade PD named Jim Ellison; when the Norse Gods start working some major world-ending mischief in the Portland area, Buffy has to use all the available resources of Slayers, Watchers, Grimm, Sentinel, Wesen allies, and one reluctant Chaos Mage, in order to thwart their plans; no pairings at all other than those in "Grimm" canon, but good detective and adventure story-telling): http://www.tthfanfic.org/Story-29246/batzulger+Not+a+Dream+Fairy+Tale+or+Imaginary+Story.htm
Harry Potter:
"White Knights and Dark Lords" SERIES by Sherza (the summer before Harry's 5th year at Hogwarts, the new Watchers' Council -- specifically, Giles and the Scoobies -- learn of Voldemort's 'rebirth' and a prophecy that should've been Council business all along; Xander and his platonic partner in mayhem and do-gooding, Spike, take on the job of rescuing Harry from the Dursleys and training him to actually survive, along with Harry's family of choice, Sirius and Remus; Excellent stories, where Voldy and the bad guys in the Ministry of Magic get very short shrift instead of being allowed to ride roughshod over everyone for several more years, but emphatically NOT for Dumbledore-lovers): http://www.tthfanfic.org/Series-2276
"Uncle Quentin's Spy" by Starfox (Harry/Hermione; 'In the summer following her 4th year at Hogwarts, Hermione Granger is visited by a great-uncle she hasn’t met before, and learns that the world is older than she thought, and that wizards are not the only ones fighting the forces of Darkness.' Travers recruits Hermione and Harry for future work with the Council and provides extra training and resources for the fight against Voldemort, including the Slayer, India Cohen): http://www.tthfanfic.org/Story-31004/Starfox+Uncle+Quentin+s+Spy.htm
"Moon Magic" by Litgal (Faith/Severus Snape! Riley gets pulled into an alternate world, and Faith goes after him, only to find herself with an unexpected ally and partner): http://www.tthfanfic.org/Story-14293/litgal+Moon+Magic.htm or http://litgal.brinkster.net/Moon/Magic1.htm
"The Flat Next Door" by Tassos (the summer after Order of the Phoenix, Harry and the Dursleys are forced to relocate to an apartment next door to post-'Chosen' Giles, where Harry finds unexpected understanding and grief counseling): http://www.tthfanfic.org/Story-6136/Tassos+The+Flat+Next+Door.htm
"The Time-Turner" by Merisida (instead of running away to L.A. after "Becoming", Buffy goes to England and stumbles on a whole different kind of weirdness, with the opportunity to change the whole history of The Boy Who Lived, for good or ill): http://www.tthfanfic.org/Story-29981/Merisida+The+Time+Turner.htm
WIP "Harry's New Mum" by SSanchez (Buffy happens upon Vernon abusing young Harry after the events at the zoo at the start of the first book and takes him home with her to the Slayers' school in England, where Willow's wards and her own strength enable her to give her adoptive son a much better life; not updated since January 2014, but still worth re-reading): http://www.tthfanfic.org/Story-29705/SSanchez+Harry+s+New+Mum.htm
Heroes:
"Interventions" SERIES by Penfold: http://www.tthfanfic.org/Series-1461
Highlander:
"A Week Away" by Jinni (Willow/Methos; Willow borrows family friend Duncan's cabin to get away and clear her head, but another friend of Duncan's drops by with the same intention, and things get complicated): http://www.tthfanfic.org/Story-1103/Jinni+A+Week+Away.htm
"Demons We Share" SERIES by Jinni (Willow/Methos):
1) "Demons We Share" http://www.tthfanfic.org/Story-75/Jinni+Demons+We+Share.htm
2) "What Are We Doing?" http://www.tthfanfic.org/Story-909/Jinni+What+Are+We+Doing.htm
"Death and the End of the World" by Stacia (Willow/Methos): http://www.tthfanfic.org/Story-1091/Stacia+Death+and+the+End+of+the+World.htm
"The Rhymer and the Ancient Mariner" by SpikeNDru (newly souled Spike meets Methos): http://www.tthfanfic.org/Story-7300/spikeNdru+The+Rhymer+and+the+Ancient+Mariner.htm
"Tomorrow, Tomorrow, and Tomorrow" by FaithUnbreakable (Buffy/Methos): http://www.tthfanfic.org/Story-16412/FaithUnbreakable+Tomorrow+Tomorrow+and+Tomorrow.htm
"Absolute Freedom" by FaithUnbreakable (Buffy/Methos; award winner for 2005): http://www.tthfanfic.org/Story-6104/FaithUnbreakable+Absolute+Freedom.htm
"The Buffy and Methos Chronicles" by Belladonna (decent Buffy/Methos, with friendships with Richie and Duncan): http://www.tthfanfic.org/Story-12257/Belladonna+The+Buffy+and+Methos+Chronicles.htm
"Life and Times of Dawn Summers, College Student" by Mei (actually a series of stories about Dawn's first semester of college in Seacouver, where she dates Richie Ryan and reluctantly introduces the immortals to her side of the 'weird' spectrum, slaying vampires and stopping apocalypses; now complete): http://www.tthfanfic.org/Story-1574/Mei+Life+and+Times+of+Dawn+Summers+College+Student.htm
"Slay Hard" by MMcGregor (Xander plays the Bruce Willis role when W&H office building is taken over by evil Immortals and their demon minions): http://www.tthfanfic.org/Story-6435-2/MMcGregor+Slay+Hard.htm
"A Watcher's Son" by AlecStar (primary crossover is with The Sentinel, but then Methos gets recruited in later chapters to become a Slayer Watcher, and things get even more interesting): http://www.booksandtales.com/fanfiction/awsindex.php
"Captive Love" by KaylaShay (Dawn/Methos; Dawn's romance with her ancient languages professor, Adam Pierson, takes an unexpected turn when someone from Methos' past decides to use her against him): http://www.tthfanfic.org/Story-9910/KaylaShay+Captive+Love.htm
"Adventures in Babysitting" by Demona (one-shot; Dawn gets kidnapped again and takes Buffy's new boyfriend Adam Pierson along for the ride): http://www.tthfanfic.org/Story-9978/Demona+Adventures+in+Babysitting.htm
(WIP) "Spike's Way" SERIES by OracleHolly (post-NFA for the most part, with second and longest story of this 4-part Spuffy series incomplete at 18 out of a possible 25 chapters since December 2007, but still worth re-reading): http://www.tthfanfic.org/Series-644 (or http://oracleholly.livejournal.com/tag/verse%3A%20spike%27s%20way, or http://www.bloodshedverse.com/stories.php?go=chapters&no=1023)
(WIP) "Puzzled" by LisaF (post-"Chosen" Dawn solves a linguistic puzzle that brings her to the attention of a number of experts, including 'Adam Pierson', who sets out to solve the puzzle of HER; hasn't been updated since December 2009, unfortunately, just when it was really getting going): http://www.tthfanfic.org/Story-19095/LisaF+Puzzled.htm
(WIP) "Looking for Acceptance" by Methos/Methos2523 (after Joyce's death in season 5, Buffy discovers that her birth father was actually supposed to be her mother's then-boyfriend Adam Pierson . . . who's alive and well and living in Seacouver, so she and Dawn decide to visit and introduce themselves; last updated July 2009, unfortunately [recently removed from TtH, but author intends to re-write and re-post on fanfiction.net, eventually]): first 5 of the 6 chapters so far can be read in cached copy at http://web.archive.org/web/20090708105828/http://www.tthfanfic.org/Story-13298/Methos+Looking+for+acceptance.htm, with chapter 6 at http://web.archive.org/web/20090727053702/http://www.tthfanfic.org/Story-13298-6/Methos+Looking+for+acceptance.htm.
House M.D.:
"Xander's New House" by DeepBlueJoy (one year after "Chosen", Xander moves to Princeton, just in time to enlist his surprise real bio-dad and some colleagues to help with the battle in L.A.): http://www.tthfanfic.org/Story-21362/DeepBlueJoy+Xander+s+New+House.htm
"Lost and Found" by NotJana (four years after "Chosen", and after yet another gut-wrenching bereavement, Buffy moves to Princeton to study physical therapy and ends up working on more than just House's sore leg; Buffy/House): http://www.tthfanfic.org/Story-16292/NotJana+Lost+and+Found.htm
"Sleeping In" SERIES by Mistral (visiting Dawn at Princeton University, Xander is struck with a strange sleeping malady that puzzles House and his team almost as much as do the extraordinary young women who gather around the sleeping man's bedside in the hospital): http://www.tthfanfic.org/Series-2941
"Who's Your Baby's Daddy?" SERIES by mmooch (as part of the Initiative's experimentation, Maggie Walsh had Buffy secretly impregnated with an illicit sperm sample, which requires Buffy and Giles to do some digging and traveling to meet the potential Dads and find out if any of them are likely to be actual decent father material; multiple crossovers, but one major -- and very angsty, in the end -- cross is with 'House'): http://www.tthfanfic.org/Series-1449
"The Ass" by Serenity (Buffy/House -- fluffy): http://www.tthfanfic.org/Story-14256/Serenity+The+Ass.htm
(WIP) "House's Key" by Sevangel (Dawn/House; abandoned just shy of completion in 2008, but still worth re-reading): http://www.tthfanfic.org/Story-10406/sevangel+House+s+Key.htm
'In Death' series:
"Little Old Ladies" by Vogonguard (J.D. Robb's police detective of the future meets an elderly Buffy Summers and Willow Rosenberg, in the course of investigating a new 'Bringer'-related homicide, and comes face to face with the world of the supernatural): http://www.tthfanfic.org/Story-14603/vogonguard+Little+Old+Ladies.htm
Leverage:
"Different Kinds of Knights" SERIES by JediButtercup ("The Soul Job", where Eliot enlists his team's aid in freeing twin brother Lindsey from his W&H contract during AtS season 5, and a collection of Buffy/Eliot follow-ups): http://www.tthfanfic.org/Series-2072
"The Lullaby Job" SERIES by toots (Dawn and Connor are re-born as Eliot's twin babies, raised by the 'Leverage' crew as an extended and uniquely functional little family; Eliot/Parker/Hardison, eventually): http://www.tthfanfic.org/Series-2280
"The Council Job" by toots (Connor is Eliot's brother -- sort of! -- and comes to Eliot and his crew for help when Dawn's latest kidnapper turns out to be human): http://www.tthfanfic.org/Story-20559-6/toots+The+Council+Job.htm
"Convergence" SERIES by txfantasystar (Eliot is Lindsey, reformed, and 8 years later Angel comes back into his life, asking for help from Eliot and his team): http://www.tthfanfic.org/Series-2023
Lois & Clark:
"Strong" by Shayne T (Lois becomes a Slayer just before she's reluctantly assigned a new partner, Clark Kent, and sent to investigate the Sunnydale sinkhole): http://www.tthfanfic.org/Story-13056/ShayneT+Strong.htm or http://www.lcfanfic.com/stories/2007/strong.txt
"California Cousin" by MarcusRowland (the Smallville sheriff asks Lois and Clark to look into the fate of her Sunnydale relatives the Harrises, post-'Chosen'): http://www.tthfanfic.org/Story-8333/MarcusRowland+California+Cousin.htm or http://archiveofourown.org/works/84037/chapters/113186
"Heard on High" by Jinni (amusing Willow/Clark one-shot): http://www.tthfanfic.org/Story-2421/Jinni+Heard+on+High.htm
Magnificent 7:
"Childhood Lost" SERIES by HiltonK (Xander is the son Ezra Standish never knew he'd fathered, until after the fall of Sunnydale): http://www.tthfanfic.org/Series-1404
Marvel Universe:
"Star Spangled Man" by Jaded (Buffy and Dawn grew up hearing their maternal grandmother's tales of her work with Captain America during WWII, only to meet up with the man himself and his new team after the battle with the Chitauri): http://www.tthfanfic.org/Story-27452/Jaded+Star+Spangled+Man.htm
"Personal Assistants, Super Heroes, & World Save-age" SERIES by Crunchysunrises (five times Buffy met Tony Stark, two times he offered her a job, and the one time she accepted -- culminated with an alternate ending to 3.01 "Anne", with a sequel focused on Pepper Potts' impressions of Buffy): http://www.tthfanfic.org/Series-3020
"The Captain America Type" and sequel "A Family Barbecue" by Brokenmimir (Buffy starts dating the cute neighbor who works out at her gym, and they discover they have even more in common than they thought: http://www.tthfanfic.org/Story-28872/brokenmimir+The+Captain+America+Type.htm and http://www.tthfanfic.org/Story-29292/brokenmimir+A+Family+Barbecue.htm
"It's an Acronym, Actually" SERIES by CaptainBoulanger (Coulson and Agent May from "Agents of S.H.I.E.L.D." cross paths with the Scoobies in Sunnydale, and their paths just keep crossing, to mutual benefit; additional minor cross with C.S. Lewis): http://www.tthfanfic.org/Series-2880
"Best Job Share Ever?" by JediButtercup (Buffy goes to work part-time for Nick Fury, as Tony Stark's personal assistant and wrangler): http://www.tthfanfic.org/Story-27812/jedibuttercup+Best+Job+Share+Ever.htm
"New Dawn" SERIES by ElzaCBoe (Dawn was created as Buffy's infant daughter in season 5, instead of as a teenaged sister, and years later Tony Stark is shocked to learn he fathered a child; badly in need of proof-reading, but still engaging): http://www.tthfanfic.org/Series-2769
"The Genius Curse" by DrakePendragon (Fred goes to work for Tony Stark instead of joining Angel and the rest at Wolfram & Hart, and that makes all the difference, you see): http://www.tthfanfic.org/Story-23715/DrakePendragon+The+Genius+Curse.htm
WIP "Fortune Days" by Jezaeiri (still being updated slowly, due to author's illness, but very much a living story; goes AU near the end of season 2, with Joyce's death at the hands of Angelus and Buffy's discovery -- AFTER going postal on Angelus, Spike, and Dru -- that her real father is Tony Stark, currently missing in Afghanistan): http://www.tthfanfic.org/Story-27630/jezaeiri+Fortune+Days.htm
WIP "Buffy's Hammer" by Becuzitswrong (stalled at 10 chapters since April 2010, but very enjoyable; at the end of season 5, Buffy's jump into the portal brings her out of a very different doorway in to the Baxter Building in a distant universe, where her Troll Hammer has merged with the powers of Mjolnir): http://www.tthfanfic.org/Story-15272/becuzitswrong+Buffy+s+Hammer.htm
"Enigma" SERIES by Batzulger (femslash; Buffy's leap into the portal at the end of season 5 lands her in the Marvel 'verse, where she becomes part of the superhero crowd and She-Hulk's girlfriend): http://www.tthfanfic.org/Series-1982
M*A*S*H:
"Shoveling" by PaBurke (retired and widowered Dr. Hawkeye Pierce gets drawn into the lives of his next-door neighbors in Cleveland, who happen to be a bunch of Slayers and Scoobies; 100 chapters of wonderful, touching story-telling, with some of Hawkeye's old Army friends also lending aid and comfort to the Slayers' cause): http://www.tthfanfic.org/Story-7661/PaBurke+Shoveling.htm
"A House by the Cove" by Freewrite (one-shot, very moving, though in need of much proof-reading; in 2004 Buffy and Dawn leave the Slaying world behind in order to reconnect with their maternal grandparents in Maine -- Hawkeye and Margaret Houlihan Pierce): http://www.tthfanfic.org/Story-7113/Freewrite+A+house+by+the+Cove.htm
Miles Vorkosigan 'verse:
"The Vor Slayer" by Vogonguard (Miles' daughter Helen is called as a Slayer, uncle Ivan actually turns out to be quite handy in the end): http://www.tthfanfic.org/Story-7765/vogonguard+The+Vor+Slayer.htm.
Sequel to Don Sample's short fic "With a Star": http://www.tthfanfic.org/Story-2251/DonSample+With+a+Star.htm
"The Taura-Tara Nexus" by Keswindhover (Sergeant Taura gets some unexpected ghostly help as she nears the end of her too-short life): http://www.tthfanfic.org/Story-11046/Keswindhover+The+Taura-Tara+Nexus.htm
N.C.I.S.:
"Little Brother" by NotJana (Xander is Abby's half-brother, but hasn't had much contact with her in recent years, so post-"Chosen" his female friends talk him into paying her a visit, leading to some close brushes with the Slayers' world on the part of various NCIS team members): http://www.tthfanfic.org/Story-19827/NotJana+Little+Brother.htm
"Chaos Theory" by Rainne (Kate/Gibbs, and eventual surprise NCIS agent pairing for Buffy; a magical accident in England causes a rift in space-time in D.C., and Kate Todd finds herself back in NCIS headquarters with no idea that she's been dead for two years; Buffy and Kate become friends and co-workers, and they help each other through some heavy emotional work): http://www.tthfanfic.org/Story-15667/Rainne+Chaos+Theory.htm
"Who's Your Baby's Daddy?" SERIES by mmooch (As part of the Initiative's experimentation, Maggie Walsh has Buffy secretly impregnated with an illicit sperm sample, which requires Buffy and Giles to do some digging and traveling to meet the potential Dads and find out if any of them are likely to be actual decent father material; multiple crossovers, but one major --and less angsty -- cross is with NCIS): http://www.tthfanfic.org/Series-1449
"Pigtails and Tweed" by Samarkand (Giles/Abby, and the two can get more than a little kinky in their bedroom antics at times): http://www.tthfanfic.org/Story-20313/Samarkand+Pigtails+and+Tweed.htm
"A Little DiNozzo" by toots (Buffy uses Tony's anonymous sperm donation to get pregnant, and then has to track him down six years later in order to get a transfusion to save her son's life): http://www.tthfanfic.org/Story-19445/toots+A+Little+DiNozzo.htm
(WIP) "Bring Up Your Dead" SERIES by grundy (first story is complete, and second story -- detailing just how Ziva's cousin Willow was involved in Ari and Caitlin both still being alive and together after all these years -- is a WIP): 1) http://www.tthfanfic.org/Story-27882/grundy+Bring+Up+Your+Dead.htm and 2) http://www.tthfanfic.org/Story-27943/grundy+Before+Twilight.htm.
(WIP) "Dawn's NCIS" SERIES by Sevangel (Dawn is Kelly Gibbs): http://www.tthfanfic.org/Series-1381
Numb3rs:
"Mathematics and Magic" SERIES by JessRS (Buffy/Charlie friendship, with something more; Buffy saves young Charlie from a vampire during her summer in L.A. after "Becoming", and things go AU from there): http://www.tthfanfic.org/Series-1194
"In Another Life" SERIES by Lyl (Willow/Don; amnesiac Willow, post-series): http://www.tthfanfic.org/Series-1492
Pitch Black/Chronicles of Riddick:
"Just the Way He Likes It" by Jedibuttercup (SHORT-ish fic, Riddick/Buffy): http://www.tthfanfic.org/Story-24081/jedibuttercup+Just+The+Way+He+Likes+It.htm
"The Primitive Side" SERIES by Jedibuttercup (series of short fics, pre-Riddick/Buffy): http://archiveofourown.org/series/1499 or http://www.tthfanfic.org/Series-48
"The (Real) Chronicles of Riddick" by msgordo (one-shot crack!fic, with Dawn and Conner joining Riddick and Kyra in their battle against the Necros, just for s**ts and giggles): http://www.tthfanfic.org/Story-7057/msgordo+The+Real+Chronicles+of+Riddick.htm
"The Restless Chronicles" by Cjsplace (Buffy/Riddick): http://www.tthfanfic.org/Story-8295/cjsplace+The+Restless+Chronicles.htm
Riverworld:
"Violence and Variations" SERIES by Kerrykhat (series of short fics, with a really intriguing Buffy/Burton thread running through, based on the 2nd miniseries where Peter Winger played 19th century explorer and author Sir Richard Burton): http://www.tthfanfic.org/Series-2348
Roswell:
"BtVS/Roswell" SERIES by Aesop (Liz is called as Slayer and Spike becomes her Watcher/trainer, as I recall -- very good): http://www.tthfanfic.org/Series-62 or http://www.tthfanfic.org/AuthorStories-2418/aesop2.htm (final story "Once Burned" is only posted on fanfiction.net: http://www.fanfiction.net/s/2094218/1/Once_Burned)
"A Matter of Trust" by Jinni (Willow-centric; Willow and AI gang rescue Michael Guerin from W&H): http://www.tthfanfic.org/Story-3199/Jinni+A+Matter+of+Trust.htm
"Goodbye and Hello" by Duchess (Xander-centric; Max goes off to Antar with Tess, and Xander drives to Roswell instead of Oxnard, where he ends up becoming a permanent part of the group; had remained technically unfinished at the end of chapter 19 for several years, though it felt pretty done, but author started updating again on 6/1013, with some promising new twists): http://www.tthfanfic.org/Story-9257/Duchess+Goodbye+and+Hello.htm
Sherlock:
"The Myffy Chronicles" SERIES by Jaded (Buffy/Mycroft! 13 stories, totaling under 22,000 words total; surprisingly engaging romance, including Dawn's eventual, unorthodox love connection): http://www.tthfanfic.org/Series-2495
Smallville:
"Smallville Glory" by ShayneT (Buffy and co. come to Smallville seeking someone strong enough to fight off the Hellgod Glory; Lex Luthor becomes intrigued by the potential of magic, and Willow discovers that Kryptonite can boost her power): http://www.tthfanfic.org/Story-21319/ShayneT+Smallville+Glory.htm
"Dawn's Fine" by Abra/Abra de Winter (Dawn/Brainiac; Brainiac/Prof. Milton Fine based his human form on a long-dead minor poet, and is intrigued when new student Dawn Summers reacts so strongly to him): http://www.tthfanfic.org/Story-8931/Abra+Dawn+s+Fine.htm (also on other sites, including http://buffy.adultfanfiction.net/story.php?no=600005331,http://archive2.livejournal.com/12828.html, and http://www.fanfiction.net/s/2880861/1/Dawns_Fine)
"The Date" SERIES by LastScorpion (Clark/Dawn, eventual Lex/Buffy; written in early season 2 of SV and season 7 of BtVS, so goes very AU for both series; Dawn and Clark go on a first date at the end of their freshman year at Metropolis University, which actually turns into a double date with Buffy and Lex, followed by major slayage, followed by Buffy 'outing' Superman as Clark Kent to Lex, and that's just the first story in the series!): http://www.tthfanfic.org/Series-1006 or http://archiveofourown.org/series/1481 (see also prequel and sequel chapters in "What Child is This"/"Kent Family Secret": http://archiveofourown.org/works/112992/chapters/157271, or https://www.fanfiction.net/s/1176995/1/What-Child-is-This and https://www.fanfiction.net/s/1183406/1/Kent-Family-Secret)
"World of Perpetual Wednesday, World without Superman" by LastScorpion (in an AU version of "The Date" series universe, where Dawn turned down Clark's first and only date invitation, Dr. Dawn Summers lets Superman talk her into sending him across space and back in time, and then finds herself in an AU version of her own Sunnydale where Buffy is alone, along with two different versions of Lex Luthor): http://www.tthfanfic.org/Story-6161/LastScorpion+World+of+Perpetual+Wednesday+World+w+o+Superman.htm, or http://archiveofourown.org/works/134412/chapters/192329
"Crossed Boundaries" SERIES by courderouge2006 (Clark/Buffy; after the angsty end of SV season 8 Clark comes to Cleveland, doing the 'lone vigilante' thing, and crosses paths with someone who's surprisingly like him): 1) https://www.fanfiction.net/s/5890666/1/Crossed-Boundaries; 2) https://www.fanfiction.net/s/5892969/1/You-Can-Take-the-Slayer-out-of-the-City; 3) https://www.fanfiction.net/s/5900157/1/Meet-the-Family-The-WHOLE-Family
"Small Towns and Hell Mouths" SERIES by courderouge2006 (Clark/Chloe, Buffy/Spike; BtVS late season 7 meets SV early season 5): 1) https://www.fanfiction.net/s/3126945/1/Small-Towns-and-Hell-Mouths; 2) https://www.fanfiction.net/s/3162200/1/Raising-Hell-Down-on-the-Farm
"Nighthawks" by SpaceAnJL (very funny short fic from 2002, set in an AU Smallville future, in which a Lex Luthor who knows his best friend is a flying alien walks into a bar and meets Spike and John Constantine, so they can drown their relationship sorrows together, and then hit Vegas . . . and Ethan Rayne; implied Chloe/Lex and Spike/Buffy, with a brief Constantine/Zatanna fling): http://www.tthfanfic.org/Story-28301/SpaceAnJL+Nighthawks.htm
"Memory" by nowhereman (Clark and Chloe visit Smallville on a Torch-related inquiry, and Clark gets hit by the 'Tabula Rasa' spell along with the Scoobies in "The Magic Box"): http://www.tthfanfic.org/Story-21815/nowhereman+Memory.htm, or https://www.fanfiction.net/s/5833118/1/Memory
"Where the Sun Don't Shine" by nowhereman (16-year-old Clark feels compelled to help when he hears of L.A.'s plight in AtS season 4, and so impresses Faith during the battle against the Beast that she and Willow ask him to accompany them to Sunnydale, to help out with the First; EXCELLENT story, worth savoring and re-reading): http://www.tthfanfic.org/Story-31045/nowhereman+Where+the+Sun+don+t+Shine.htm, or https://www.fanfiction.net/s/11162118/1/Where-the-Sun-don-t-Shine
"A Strange Meeting Place" SERIES by Chunk127/Chunkman (Clark/Buffy; needs more proof-reading, but definitely re-readable; Clark meets Buffy in Heaven when he dies from a gunshot wound in season 4 of SV, and they bond deeply before Willow resurrects Buffy and Jor-El restores Clark; over a year later, Clark hears that Sunnydale's being evacuated and runs there to help, on the off-chance that 'Buffy Summers' wasn't just a dream as everyone else insists; the final battle of Sunnydale goes somewhat differently with Clark on hand to help, and the sequel story has many more SV/BtVS pairings coming about): http://www.tthfanfic.org/Series-2534 or http://www.fanfiction.net/s/7722111/1/A-Strange-Meeting-Place (see also sequel chapters: http://www.fanfiction.net/s/7900552/1/Weddings-Phantoms-and-Men-in-Tights and http://www.fanfiction.net/s/8785369/1/A-Doomed-Wedding)
"Aliens, Mutants, and Demons" SERIES by BlueGold (SV/X-Men/BtVS cross, with only the 3rd and final story bringing in BtVS; Clark and Lex get together early in SV's timeline, and that makes a world of difference for everyone, including most of the misguided 'meteor mutants'): http://www.tthfanfic.org/Series-696
"Wish" by meridian_rose (While subbing for another Vengeance Demon with a different clientele, late-season-6 Anyanka offers early season 2 Lionel Luthor a wish; Lionel's wish undoes his blindness but messes everything else up, and in desperation he turns to his new reality's Chloe Sullivan to make a corrective wish): http://archiveofourown.org/works/325845 or http://www.fanfiction.net/s/7768156/1/Wish
link to 'Stargate'-related BtVS crossover fanfic faves and recs
Star Trek (TNG):
"The Way It Should Have Been" by Burmafrdnow (Q gets bored and decides to make it possible for Buffy to summon assistance from the crew of Picard's Enterprise, including a bunch of Klingons eager to practice their skills on some demon armies): http://www.tthfanfic.org/Story-24950/burmafrdnow+The+way+it+should+have+been.htm
"Legend" by ShayneT (Buffy's cryotank and the Buffybot are both recovered by Data when breaking out of Kivas Fadjol's collection, and the Federation wants to put Buffy on trial, at the demand of the Cardassians, because she's an inspiration to the Bajorans; Meanwhile, Spike's working for Section 31!): http://www.tthfanfic.org/Story-24717/ShayneT+Legend.htm
Star Trek (2009) or TOS:
"Terms of Enlistment" by Crunchysunrises (young officer Christopher Pike meets a bartender with the historically rare name of 'Buffy Summers' and ends up trying to recruit her . . . for the good of Starfleet, and not at all because he wants to have lots of sex with her! Really!): http://www.tthfanfic.org/Story-28199/Crunchysunrises+Terms+of+Enlistment.htm
"But Never Broken" SERIES by grundy (Faith winds up on Nero's ship, in a universe and timeline far from her own; 11 very short fics and a couple of drabbles): http://www.tthfanfic.org/Series-1963
"Fish Climbing Trees" SERIES by Polgara (Buffy/Bones): http://www.tthfanfic.org/Series-2642
"Bound in Story" SERIES by MochasNMayhem [formerly 'Koohii Cafe'] (Buffy & Kirk friendship; at the end of the original 5-year mission, a restless Captain Kirk finds an irresistible mystery in an antique trunk filled with weapons, crosses, and holy water, along with a chance to retrieve Buffy from the demon dimension she'd been trapped in since the destruction of Sunnydale; 26 chapters in all, only the first 19 of which were posted on TtH): http://archiveofourown.org/series/301023 [see also http://www.tthfanfic.org/Story-31227/MochasNMayhem+Bound+in+Story.htm for first 19 chapters]
Terra Nova:
"Dancing With Dinosaurs" SERIES by JediButtercup (Commander Taylor is surprised to find his "Auntie Liz" arriving with the latest migration, and not looking a day older than when he knew her as a boy; first story is complete, but second is a WIP) http://www.tthfanfic.org/Series-2502 or http://archiveofourown.org/series/16965
The Sentinel:
"A Watcher's Son" by AlecStar (primary crossover is with The Sentinel, with Rupert Giles turning out to be Blair's unknown father in the latter part of season five of BtVS, but then Methos gets recruited in later, post-"Chosen" chapters to become a Slayer Watcher, and things get even more interesting): http://www.booksandtales.com/fanfiction/awsindex.php
"Not a Dream, Fairy Tale, or Imaginary Story" by Batzulger (primarily a "Grimm"/BtVS crossover epic, with a secondary cross with "The Sentinel" in the form of a now Guide-less Jim Ellison, and a minor cross with "Fringe"; many years post-Chosen, Buffy and Dawn move from Cleveland to Portland, where Dawn teaches at a local university while Buffy works as a homicide detective, coming to terms with the heretofore largely unknown world of Wesen and Grimms and partnering with another recent transfer from Cascade PD named Jim Ellison; when the Norse Gods start working some major world-ending mischief in the Portland area, Buffy has to use all the available resources of Slayers, Watchers, Grimm, Sentinel, Wesen allies, and one reluctant Chaos Mage, in order to thwart their plans; no pairings at all other than those in "Grimm" canon, but good detective and adventure story-telling): http://www.tthfanfic.org/Story-29246/batzulger+Not+a+Dream+Fairy+Tale+or+Imaginary+Story.htm
"The Kin Series" by litgal (Blair has a relatively minor role in the two main stories, which focus on Angel becoming Xander's guardian in High School and then his lover in L.A.): http://www.tthfanfic.org/Series-1350 (or http://litgal.brinkster.net/Kin/Bumbling.htm and http://litgal.brinkster.net/Kin/Soul1.htm)
"Protecting the Light" by K-Lyn (Faith runs off to Cascade instead of L.A. after the body-swap in BtVS season 4): http://www.wolfpanther.com/stories/protecting.html
[sequel story is crossover between TS and First Wave, "Conquering the Spirit World" (the aliens target Blair , and Cade Foster comes to Cascade to enlist his help): http://www.wolfpanther.com/stories/conquering.html
"Of Shadows and Demons" by Mackie (BtVS/TS cross):
http://100megsfree3.com/fauxpaws08/mackie/shadows1.html
http://100megsfree3.com/fauxpaws08/mackie/demons2.html
Follow-up to "Of Shadows and Demons" by Mackie: http://100megsfree3.com/fauxpaws08/mackie/consume.html ("Interlude: Consumed by the Fire")
The Vampire Diaries:
"Sassy" by Echo (delightfully snarky and sexy Damon/Dawn, set early 2nd season for TVD): http://www.tthfanfic.org/Story-23417/echo+Sassy.htm
"And After the Storm" by Ava (one-shot -- so far! -- where Buffy gets stuck in a different dimension, apparently devoid of the supernatural and anyone she knows from back home, until she looks up her mother's family in Virginia, the Lockwoods of Mystic Falls; too bad she didn't know she'd inherited that pesky werewolf curse until it was too late): http://www.tthfanfic.org/Story-26928/Ava+After+the+Storm.htm
"Trouble Ahead" by Azure (Buffy is Jenna's younger sister and therefore aunt to Elena, and Damon becomes fascinated by her when she comes to visit in TVD season one; see also the sequel of sorts, "Enigma of an Aunt"): http://www.tthfanfic.org/Story-27009/Azure+Trouble+Ahead.htm and http://www.tthfanfic.org/Story-27043/Azure+Enigma+of+an+Aunt.htm
"Many Possible Vampire Husbands of Buffy Summers" by hellbells (multi-cross, desperately in need of proof-reading like all of this author's work; Buffy becomes immortal, marries Damon Salvatore, and in the second half of the story they end up aiding River Tam during the Firefly episode "Objects in Space"): http://www.tthfanfic.org/Story-27869/hellbells+Many+possible+vampire+husbands+of+Buffy+Summer.htm
"Family Matters" by hellbells (Buffy/Damon; cute short-fic, desperately in need of proof-reading, with sequel "Then They Were Two"): http://www.tthfanfic.org/Story-25697/hellbells+Family+Matters.htm and http://www.tthfanfic.org/Story-27887/hellbells+Then+they+were+two.htm
Tom Clancy's 'Rainbow Six':
"Rainbow Over Sunnydale" SERIES by JoeB (when the Initiative goes AWOL and tries to destroy the world, President Jack Ryan tasks Rainbow to defend the Hellmouth; additional major crossovers with "The Mummy" and "Charmed" in later stories, as well as "Die Hard" and "The New Avengers"): http://www.tthfanfic.org/Series-883
The West Wing:
"Potential" SERIES by kurttrout (2 short fics, exploring the idea of Helen Santos as a former Potential Slayer who's recruited to help train and support newly Called slayers in the Houston area while her husband's still in Congress, and who puts Buffy on her personal staff during the Santos presidential campaign, giving Josh some serious concern about what the three blondes -- Helen, Buffy, and Donna Moss -- get up to at times): http://www.tthfanfic.org/Series-2542
True Blood:
"New Dimension, Same Worries" SERIES by Polgara (3 short fics, in which Buffy deals with being stuck in a different dimension where snarky vampires STILL want to flirt with her): http://www.tthfanfic.org/Series-730
"Run" by FaithUnbreakable (goes AU for Buffy during "Earshot", leaving a telepathic Buffy on the run and meeting up with Eric at an opportune moment): http://www.tthfanfic.org/Story-18690/FaithUnbreakable+Run.htm (see also latest follow-up "A Thousand More", in which Buffy and Godric return to Eric after restoring Godric's will to unlive: http://www.tthfanfic.org/Story-28784-11/FaithUnbreakable+Wishlist+2012.htm, followed by 'coda' fic, "Flesh and Blood", in which Angel and Willow find a surprise when they visit Fangtasia on unrelated business, 20 years after Buffy's supposed death: http://www.tthfanfic.org/Story-23837-6/FaithUnbreakable+Wishlist+2010.htm)
"The Cure for Boredom" by SweetChi (Buffy/Eric; Buffy is bored after "Chosen", but an unexpected trip to the 'True Blood' dimension may be just what she needs; had been stalled at 43 chapters since June 2012, but chapter 44 was added Sept. 2013): http://www.tthfanfic.org/Story-24723-43/SweetChi+The+Cure+for+Boredom.htm
Underworld:
"Opposites Attract and All That Jazz" SERIES by houses (Lucian was delivered to his lawyers for treatment at the end of the first Underworld movie, and Fred discovers him when reviewing her new department's records at the start of AtS season 5): http://www.tthfanfic.org/Series-25
"Underpants World" by echo (Tara ended up in Michael and Selene's world, where Kraven thought it would be a good idea to steal her pants): http://www.tthfanfic.org/Story-6461/echo+Underpants+World.htm
"The Other Side" by oxnate (Xander dresses as an American Death Dealer for Halloween, and remains transformed after the spell is broken, leading to a very different outcome for the next few months of season 2 and a different side of the Yellow Crayon Speech; minor cross with "Highlander" only in research on Dark Quickenings near the end): http://www.tthfanfic.org/Story-28433/Oxnate+The+Other+Side.htm
(WIP) "Armistice" by JoeB (on the run with Selene from Vampire vengeance after the first movie, Michael is advised by his father Hank Summers to seek out his previously unknown half-sister, the Slayer, for help): http://www.tthfanfic.org/Story-14026/JoeB+Armistice.htm
"Savior" by Serenity (short-fic in which Buffy saves Lucian at the end of the first movie): http://www.tthfanfic.org/Story-17580/Serenity+Savior.htm
Xena: Warrior Princess:
"Thrust Back" SERIES by Jinni (Willow/Ares; very amusing, as I recall): http://www.tthfanfic.org/Series-262
"Not-So-Blithe Spirits" SERIES by RevDorothyL (Buffy is the latest re-birth of Xena's soul, with many other BtVS and AtS characters also turning out to have earlier incarnations in the Xenaverse and the world of H:tLJ): http://www.tthfanfic.org/Series-521
Warning: This is my personal list of reminders, for the purposes of re-reading and recommending BtVS fics that are NOT crossed with SG1 or SGA (see my recently updated list of SG1-related crossover fanfic faves and recs for BtVS/SG1 crossovers, as well as my list of SG1 crossover fics unrelated to BtVS and list of crossover fics unrelated to BtVS or SG1), so there may well be spoilers in A FEW of the descriptions below. I'd advise you to skip reading the descriptions and just click on the links to check the stories out for yourself, if you're extremely concerned about plot or relationship spoilers. Otherwise, please enjoy this very incomplete listing of some of the stories I've enjoyed reading and re-reading over the years!
* * * * *
Batman (and/or DC Universe in general):
"JLA and the Slayers" SERIES by Nycorson (post-"Chosen" Xander finds himself forcibly sidelined by Willow and Buffy, but accepts a job offer to train newly awakening Slayers in the DC/Justice League universe, where they've never had Slayers before): http://www.tthfanfic.org/Series-2233
"Financial Supporters" by Sheilynn (Buffy/Bruce; delightful one-shot): http://www.tthfanfic.org/Story-5690-3/Sheilynn+Christmas+Falalalala-lidays.htm
"Bat Signals and Stakes" SERIES by Damia (Dawn/Dick Grayson): http://www.tthfanfic.org/Series-2367
"The Joyce Summers School for Gifted Girls" by MaeveBran (Buffy/Bruce; technically unfinished at 12 chapters, but ends in a good place): http://www.tthfanfic.org/Story-17066/MaeveBran+The+Joyce+Summers+School+for+Gifted+Girls.htm
"The Wrong Girl" by FaithUnbreakable (very DARK Buffy/Bruce fic, with coda linked at the bottom of the story; set post-The Dark Knight): http://www.tthfanfic.org/Story-18022/FaithUnbreakable+Wrong+Girl.htm
(WIP) "Gotham Slayer" by CousinMary (epic-length story of what happens when Buffy and Dawn move to Gotham after Sunnydale's destruction, where Buffy finds herself accidentally adopting a masked vigilante persona and quarreling with Batman, neither knowing that they're also dating one another as Bruce and Buffy; not updated since 2010, but still worth reading): http://www.tthfanfic.org/Story-18314/CousinMary+Gotham+Slayer.htm
(WIP) "In Darkest Night" by DWDuck (not updated since early 2011, but a wonderful 6-chapter AU in which newly ensouled Spike, still in Africa, gets chosen as successor to a dying Green Lantern and comes back to Sunnydale able to be of far more assistance to Buffy than anyone expected): https://www.fanfiction.net/s/6533732/1/In-Darkest-Night
Battlestar Galactica:
"A Bug on the Cosmic Windscreen" by missmurchison (Spike gets picked up by a Raptor and finds ways to make himself useful among the Colonials): http://www.tthfanfic.org/Story-8436/missmurchison+A+Bug+on+the+Cosmic+Windscreen.htm
Big Bang Theory:
"It's Only the End of the World" SERIES by droidgirl (Sheldon/Penny; Penny's previous encounters with 'Anne' the Vampire Slayer and with Gunn and his vampire-hunting crew prepare her somewhat for the hellish conditions in LA at the end of the AtS finale "Not Fade Away," and she and Sheldon join forces with Spike and friends to survive; HIGHLY recommended!): http://www.tthfanfic.org/Series-1986
"The Sublet Sublimation" by grundy (short but very cute; Dawn Summers sublets Leonard's room in Apartment 4A and has an 'interesting' time getting to know her new flatmate): http://www.tthfanfic.org/Story-29374/grundy+The+Sublet+Sublimation.htm
"The Undead Entropy Anomaly" by grundy (short but sweet; Dr. Dawn Summers sublets Leonard's room in Apartment 4A, but has to call Penny for reinforcements when Sheldon has an extreme reaction to learning that vampires are real): http://www.tthfanfic.org/Story-28117/grundy+The+Undead+Entropy+Anomaly.htm
"It's All About *Who* Says It" by mmooch (delightful short-fic; Sheldon/Buffy!): http://www.tthfanfic.org/Story-24180/mmooch+It+s+All+About+Who+Says+It.htm
"The Dawn Conundrum" by mmooch (3rd and final story in a series in which Buffy's allowed to R.I.P. after season 5, but can easily be read by itself; Dawn goes to live with cousin Penny in Pasadena after Buffy's funeral, rather than staying in Sunnydale, and this short-fic shows Dawn's reaction to learning about the stunt with the can-opener in the Arctic): http://www.tthfanfic.org/Story-24777/mmooch+The+Dawn+Conundrum.htm
"The Reality-Theory Convergence" by DianeCastle (Penny's new job as office manager for the LA branch of Slayers Inc. provides almost as much entertainment and satisfaction as having Buffy and some mini-Slayers as Sheldon's new upstairs neighbors): http://www.tthfanfic.org/Story-28227/DianeCastle+The+Reality-Theory+Convergence.htm
Bolo!:
"It's Not the Size of the Dog in the Fight" by Samarkand (lewd, crude, and occasionally hilarious; Xander becomes a miniature Bolo for Halloween): http://www.tthfanfic.org/Story-19725/Samarkand+It+Ain+t+The+Size+Of+The+Dog+In+The+Fight.htm
"Of the Line" by ghostwhowalks (Chloe, a Bolo with a soul, is called to be a Slayer only 1200 years after her sister Potentials were activated in "Chosen"): http://www.tthfanfic.org/Story-9996-3/ghostwhowalks+Of+The+Line.htm (first 4 chapters make a complete story, with the rest an unfinished epilogue venturing into multiple crossovers)
Chronicles of Narnia:
"To the Ground" by Faithunbreakable (Buffy gets tossed from universe to universe, spending lifetime after lifetime in unwilling service to the higher powers, until she falls into Aslan's domain and is tasked with protecting Prince Caspian . . . and manages to connect with King Peter along the way): http://www.tthfanfic.org/Story-20263/FaithUnbreakable+To+The+Ground.htm
Dark Angel:
"Family Ties" SERIES by kerrykhat (Buffy and Faith discover that their genes were used to make Max and her siblings, and they're not ones to leave their kids in the lurch, no matter how unusual or unwilling their conception may've been): http://www.tthfanfic.org/Series-1964
(WIP) "My Life for You" SERIES by Charlotte/
dharkapparition [formerly dharkcharlotte] (Buffy/Ben): http://www.tthfanfic.org/Series-882
Dexter:
"The Wolves" by FaithUnbreakable (Buffy/Dexter, pre-series for Dexter and post season 2 for BtVS): http://www.tthfanfic.org/Story-17697/FaithUnbreakable+The+Wolves.htm
"Predatory Connections" by Litgal (Spike/Dexter one-shot; very bloody, but affecting): http://www.tthfanfic.org/Story-16203/litgal+Predatory+Connections.htm
Doc Savage:
"Older and More Savage Times" SERIES by batzulger (Faith/Clark Savage IV; Slayer and part-time U.S. Marshal Faith finds an unexpected ally against supernatural threats in the latest generation of the Savage family): http://www.tthfanfic.org/Series-3058
"Nacht" SERIES by batzulger (Kennedy finds herself dumped into another universe in 1930s New York City, and invents a "Shadow"-like masked alter-ego for fighting crime and Nazis, with the eventual assistance of extraordinary people like Pat Savage and Nicola Tesla): http://www.tthfanfic.org/Series-2904
Doctor Who/Torchwood:
"Who's the Doctor?" SERIES by missmurchison (series of brief stories, starting with an AU and much more Spuffy friendly version of "As You Were" featuring the 10th Doctor and proceeding with further AU season 6 encounters with the 9th, 4th, and 7th Doctors and Dawn's ongoing friendship with the TARDIS; all 4 stories are also available on LJ at various locations): http://www.tthfanfic.org/Series-2847
"Who's the Doctor?": http://missmurchison.livejournal.com/389657.html#cutid1
"Dawn of the Doctor" (Dawn helps the newly regenerated 9th Doctor): http://missmurchison.livejournal.com/522536.html
"Where's the Doctor?" (12 brief chapters; 4th Doctor and Leela): http://seasonal-spuffy.livejournal.com/295675.html
"Buffy and the Dalek Slayers" (9 chapters; 7th Doctor and Ace): http://seasonal-spuffy.livejournal.com/424280.html (http://seasonal-spuffy.livejournal.com/tag/creator%3A%20missmurchison)
"My Immortal" SERIES by Elisi (Buffy/Jack, and later Buffy/Spike): http://www.tthfanfic.org/Series-1606
"The Doctor's Faith" SERIES by DWDuck (Faith/Ten; At least one of the Powers recognizes that Buffy needs help against the First and so arranges to set the Doctor on the case; starts just post-season 4 for the new DW and late season 7 for BtVS, and goes AU from there, with a (so far) final installment being a 'Smallville'/'Torchwood' cross): http://www.tthfanfic.org/Series-3076, or see
1) https://www.fanfiction.net/s/6363098/1/The-Doctor-s-Faith-Healing,
2) https://www.fanfiction.net/s/6433684/1/The-Angel-Has-the-Phone-Box,
3) https://www.fanfiction.net/s/6765535/1/The-Angel-s-Voice,
4) https://www.fanfiction.net/s/6608411/1/The-Doctors-and-the-Keys [unfinished since 2014], and
5) https://www.fanfiction.net/s/6055853/1/Captain-Jack-Comes-to-Smallville
"Impossible Things" SERIES by MoragMacPherson (Buffy/10th Doctor; a weeping angel sends Buffy to an alternate version of 1913, where she ends up scrubbing floors along side of Martha at a boys' school and piquing the interest of Prof. John Smith): 1) http://www.tthfanfic.org/Story-17978/MoragMacPherson+Impossible+Things.htm; 2) http://www.tthfanfic.org/Story-18638/MoragMacPherson+Sitting+Waiting+Wishing.htm
"Golden Threads" SERIES by Jaded (Jack/Ianto/Dawn; epic story of Dawn, the Scoobies, and their whole extended family becoming closely involved with Torchwood 3 and the Doctor): http://www.tthfanfic.org/Series-2155
(WIP) "Tick, Tock, One Little Clock" by Doctorsgirl (eventual Buffy/Doctor; the old pocket watch Buffy adds to her Halloween 'lady' costume is from a previously used chameleon arch transformation and funnels all the energy of the Janus spell and the Hellmouth rift into Buffy's permanent transformation, erasing her existence from the minds of her friends and family on earth; calling herself 'The Slayer', she and her companions do a lot of evil-vanquishing and running around the universe, until they find the 10th regeneration of The Doctor, no longer the last of the Time Lords; incomplete, but still well worth re-reading, as Buffy and her TARDIS crew join some of the Doctor's adventures in season four): http://www.tthfanfic.org/Story-21501/Doctorsgirl+Tick+Tock+One+little+clock.htm
"Ghost Story" by Mhalachai (Dawn meets Captain Jack): http://www.tthfanfic.org/Story-15762/Mhalachai+Ghost+Story.htm
Farscape:
"From Heaven and Hell" by Tassos (while searching for Dargo's kidnapped son, the crew of Moya find the trail leads straight through a wormhole to Los Angeles on Crichton's home planet, and the PTB send Angel to help them out, a few episodes shy of the AtS season 1 finale): http://www.tthfanfic.org/Story-5467/Tassos+From+Heaven+and+Hell.htm
"When Good Spells Go Bad" by Kennie (Willow accidentally ends up on Moya; Willow-Crichton friendship, with Crichton/Aeryn romance unthreatened): http://www.tthfanfic.org/Story-18455/Kennie+When+Good+Spells+Go+Bad.htm
Firefly:
"Well That Went Well" by MissE/ObscureEnough (while trying to hide Dawn from Glory, Dawn and her two protectors -- Xander and Faith -- end up spending time on 'Serenity' before, during, and just after the events of the movie): http://www.tthfanfic.org/Story-23376/MissE+Well+That+Went+Well.htm, or http://misse.livejournal.com/33065.html
"Collecting Xander" by Kei (post-BDM; River/Mal, eventual Zoe/Xander): http://www.tthfanfic.org/Story-15967/Kei+Collecting+Xander.htm
"Cookie Crumbs of Fate" by Crunchysunrises (Buffy is drawn forward through time, from before the start of season 4, to come to the aid of River on Serenity, and hopefully also the other children of the Academy, eventually): http://www.tthfanfic.org/Story-29296/Crunchysunrises+Cookie+Crumbs+of+Fate.htm
"I'm Here to Tell You About My Dream" by Kaela (Buffy asks Inara and Jayne to help her finally end her life): http://www.tthfanfic.org/Story-23756/kaela+I+m+here+to+tell+you+about+my+dream.htm
"Leaves on the Wind: 'Firefly' and 'Serenity' one-shots" SERIES by JediButtercup: http://www.tthfanfic.org/Series-2970
"All Made Up" by JediButtercup (The Wolf, Ram, and Hart are still messing about, and they seem to have targeted Mal's crew for particular harasshment; 4 short inter-related AtS/Firefly crossover stories): http://www.tthfanfic.org/Story-27811/jedibuttercup+All+Made+Up.htm or http://archiveofourown.org/series/9243
"Sidle Up and Smile" SERIES by JediButtercup (Buffy and Faith haven't aged since Willow's spell, and Buffy is Mal's mother): http://www.tthfanfic.org/Series-1047 or http://archiveofourown.org/series/1446
"Colors" by anaross (post BDM, Spike/Zoe friendship; either six months or 500 years after the battle in the alley behind the Hyperion, Spike finds himself stranded alone in the future, hoping somehow that Serenity and its crew will be able to help him find his way back to Buffy, while he helps River cope with her confused Slayer line memories): https://www.livejournal.com/tools/memories.bml?user=anaross&keyword=Colors&filter=all
"Our Mrs. Cobb" by Sevangel (River/Jayne and Willow/Mal/Inara): http://www.tthfanfic.org/Story-8457/sevangel+Our+Mrs+Cobb.htm
"Slayers in Space" by Sevangel (River/Jayne and Faith/Mal): http://www.tthfanfic.org/Story-7824/sevangel+Slayers+in+Space.htm
"Finding Home" by Sweetdoggie (Buffy/Jayne -- 10K word one-shot): http://www.tthfanfic.org/Story-15946/Sweetdoggie+Finding+Home.htm
"Finding My Serenity" by Cjsplace (Buffy/Mal, going AU with Buffy leaving her home dimension right after slicing up Caleb): http://www.tthfanfic.org/Story-9863/cjsplace+Finding+My+Serenity.htm
"Starting from Scratch" by agilebrit (post-NFA, Spike and Illyria jump a portal to 500 years in the future and end up meeting River when they take passage on 'Serenity'; short-ish 5K words): http://www.tthfanfic.org/Story-12185/agilebrit+Starting+from+Scratch.htm
"Another Day, Another Apocalypse" by agilebrit (a.k.a. 'babies stole my dingo') -- post NFA, Fred, Spike, Angel, AND Illyria end up on pre-BDM Serenity, in time to activate River and Zoe as slayers and fight WFH's new attempt to open a hellmouth (Jayne/Illyria!): https://www.fanfiction.net/s/2974220/1/Another-Day-Another-Apocalypse
"The Very Small Girl and the Monster" by Snickfic (Spike & River): http://archiveofourown.org/works/158455
"Many Possible Vampire Husbands of Buffy Summers" by hellbells (multi-cross, desperately in need of proof-reading like all of this author's work; Buffy becomes immortal, marries Damon Salvatore, and together they end up aiding River during "Objects in Space"): http://www.tthfanfic.org/Story-27869/hellbells+Many+possible+vampire+husbands+of+Buffy+Summer.htm
(WIP) "Goodnight Daughters" SERIES by Syriope (not updated since 2009; Buffy and River as Academy escapees): http://www.tthfanfic.org/Series-974
(WIP) "From Here to Serenity" by bastardsnow (not updated since 2007, but worth re-reading anyway; Xander and Willow hop dimensions and jump five hundred years into the future in an attempt to find Buffy after "The Gift", and they end up almost hijacking Serenity in order to get to long-lost "Earth that was", where Buffy turns out to have landed): http://www.tthfanfic.org/Story-7081/bastardsnow+From+Here+to+Serenity.htm (also at http://www.fanfiction.net/s/2703205/1/From-Here-to-Serenity or http://bastardsnow.livejournal.com/tag/fhts)
(WIP) "Book's Legacy" by JediButtercup (not updated since August 2010): http://www.tthfanfic.org/Story-7761/jedibuttercup+Book+s+Legacy.htm
(WIP) "Carving Out a Future" by Dreamfall (Xander gets magically frozen by Willow until they can find a way to save his life, which doesn't happen until the 26th century, long after everyone and everything Xander knows is gone, leaving a formerly one-eyed carpenter displaced in time and travelling the 'verse with the pre-BDM crew of Serenity; formerly stalled at 51 chapters on TtH since 2010, but updated to 54 chapters in 2018): http://www.tthfanfic.org/Story-7832/dreamfall+Carving+Out+a+Future.htm (but see also chapter 52 posted to LJ in 2011, ch. 53 in 2014, and ch. 54 & 55 in 2016: http://dreamfall-nnwm.livejournal.com/23561.html)
Galaxy Quest:
"Questing Around the Galaxy" SERIES by Lucinda (Cordelia gets a recurring role on the revived SF series 'Galaxy Quest', just in time for the worlds of aliens and demons to intersect -- Cordy/Jason Nesmith, Willow/Alex Dane, Angel/Gwen DeMarco, Fred Kwan/Laliari): http://www.tthfanfic.org/Series-178
Gargoyles:
"Defender of the Night" by MMcGregor (Xander dresses as Goliath for Halloween, and it sticks): http://www.tthfanfic.org/Story-6269/MMcGregor+Defender+of+the+Night.htm
"BtVS/Gargoyles" SERIES by Aesop (includes ST:TNG crossover in final installment of the 8-story series): http://www.tthfanfic.org/Series-156
"Heroes" by LMouse (one-shot with Buffy stuck in snowbound New York and working/semi-flirting with Brooklyn in order to take down a troublesome vamp; set before Buffy finds out that Spike's back and stuck at W&H: minor cross with the Ron Perlman Beauty and the Beast series and a few other franchises, as well): http://www.tthfanfic.org/Story-4717/LMouse+Heroes.htm
Gilmore Girls:
"A Schism in Stars Hollow" by Litmouse (Part of the "Father Goose" series, but can be read on its own; the Scoobies and significant others come to Stars Hollow for a convention of Xander-and-Faith impersonators, but discover there's more than just quirkiness afoot): http://www.tthfanfic.org/Story-10926/litmouse+A+Schism+in+Stars+Hollow+A+Father+Goose+Digression.htm
"In the Key of Major Finn" by Mhalachai (post-series for both BtVS and GG, Lorelai didn't get back together with Luke and Riley is a widower whose services have been made redundant by the multitude of Slayers, so . . .): http://www.tthfanfic.org/Story-12190/Mhalachai+In+The+Key+of+Major+Finn.htm
"Life Saver" by Belgintei (season 1 for GG and last half of season 7 for BtVS; Luke Danes has to tell 'former' Potential Lorelai Gilmore and current Potential Rory about the supernatural and evacuate them to Sunnydale to escape the Bringers, and the addition of these GG characters smooths out some of the emotional rough patches for Buffy and others in those final days; darker sequel "Life Saver II" has been stalled at an early point in the narrative since 2007, but main story is finished): http://www.tthfanfic.org/Story-7629/belgintei+Life+Saver.htm and http://www.tthfanfic.org/Story-9222/belgintei+Life+Saver+II.htm
Glee:
"Catch a Falling Star" by toots (Rachel leaves Lima to begin her Slayer training, and the Glee crew realize how much they miss her after she's gone): http://www.tthfanfic.org/Story-22113/toots+Catch+a+Falling+Star.htm
Good Eats:
"Good Slaying" by Justaguy (Buffy and Willow evaluate a new potential teacher with a unique approach to educating mini-Slayers in this delightful little ficlet): http://www.tthfanfic.org/Story-6736/justaguy+Good+Slaying.htm
Grimm:
"Not a Dream, Fairy Tale, or Imaginary Story" by Batzulger (primarily a "Grimm"/BtVS crossover epic, with a secondary cross with "The Sentinel" in the form of a now Guide-less Jim Ellison, and a minor cross with "Fringe"; many years post-Chosen, Buffy and Dawn move from Cleveland to Portland, where Dawn teaches at a local university while Buffy works as a homicide detective, coming to terms with the heretofore largely unknown world of Wesen and Grimms and partnering with another recent transfer from Cascade PD named Jim Ellison; when the Norse Gods start working some major world-ending mischief in the Portland area, Buffy has to use all the available resources of Slayers, Watchers, Grimm, Sentinel, Wesen allies, and one reluctant Chaos Mage, in order to thwart their plans; no pairings at all other than those in "Grimm" canon, but good detective and adventure story-telling): http://www.tthfanfic.org/Story-29246/batzulger+Not+a+Dream+Fairy+Tale+or+Imaginary+Story.htm
Harry Potter:
"White Knights and Dark Lords" SERIES by Sherza (the summer before Harry's 5th year at Hogwarts, the new Watchers' Council -- specifically, Giles and the Scoobies -- learn of Voldemort's 'rebirth' and a prophecy that should've been Council business all along; Xander and his platonic partner in mayhem and do-gooding, Spike, take on the job of rescuing Harry from the Dursleys and training him to actually survive, along with Harry's family of choice, Sirius and Remus; Excellent stories, where Voldy and the bad guys in the Ministry of Magic get very short shrift instead of being allowed to ride roughshod over everyone for several more years, but emphatically NOT for Dumbledore-lovers): http://www.tthfanfic.org/Series-2276
"Uncle Quentin's Spy" by Starfox (Harry/Hermione; 'In the summer following her 4th year at Hogwarts, Hermione Granger is visited by a great-uncle she hasn’t met before, and learns that the world is older than she thought, and that wizards are not the only ones fighting the forces of Darkness.' Travers recruits Hermione and Harry for future work with the Council and provides extra training and resources for the fight against Voldemort, including the Slayer, India Cohen): http://www.tthfanfic.org/Story-31004/Starfox+Uncle+Quentin+s+Spy.htm
"Moon Magic" by Litgal (Faith/Severus Snape! Riley gets pulled into an alternate world, and Faith goes after him, only to find herself with an unexpected ally and partner): http://www.tthfanfic.org/Story-14293/litgal+Moon+Magic.htm or http://litgal.brinkster.net/Moon/Magic1.htm
"The Flat Next Door" by Tassos (the summer after Order of the Phoenix, Harry and the Dursleys are forced to relocate to an apartment next door to post-'Chosen' Giles, where Harry finds unexpected understanding and grief counseling): http://www.tthfanfic.org/Story-6136/Tassos+The+Flat+Next+Door.htm
"The Time-Turner" by Merisida (instead of running away to L.A. after "Becoming", Buffy goes to England and stumbles on a whole different kind of weirdness, with the opportunity to change the whole history of The Boy Who Lived, for good or ill): http://www.tthfanfic.org/Story-29981/Merisida+The+Time+Turner.htm
WIP "Harry's New Mum" by SSanchez (Buffy happens upon Vernon abusing young Harry after the events at the zoo at the start of the first book and takes him home with her to the Slayers' school in England, where Willow's wards and her own strength enable her to give her adoptive son a much better life; not updated since January 2014, but still worth re-reading): http://www.tthfanfic.org/Story-29705/SSanchez+Harry+s+New+Mum.htm
Heroes:
"Interventions" SERIES by Penfold: http://www.tthfanfic.org/Series-1461
Highlander:
"A Week Away" by Jinni (Willow/Methos; Willow borrows family friend Duncan's cabin to get away and clear her head, but another friend of Duncan's drops by with the same intention, and things get complicated): http://www.tthfanfic.org/Story-1103/Jinni+A+Week+Away.htm
"Demons We Share" SERIES by Jinni (Willow/Methos):
1) "Demons We Share" http://www.tthfanfic.org/Story-75/Jinni+Demons+We+Share.htm
2) "What Are We Doing?" http://www.tthfanfic.org/Story-909/Jinni+What+Are+We+Doing.htm
"Death and the End of the World" by Stacia (Willow/Methos): http://www.tthfanfic.org/Story-1091/Stacia+Death+and+the+End+of+the+World.htm
"The Rhymer and the Ancient Mariner" by SpikeNDru (newly souled Spike meets Methos): http://www.tthfanfic.org/Story-7300/spikeNdru+The+Rhymer+and+the+Ancient+Mariner.htm
"Tomorrow, Tomorrow, and Tomorrow" by FaithUnbreakable (Buffy/Methos): http://www.tthfanfic.org/Story-16412/FaithUnbreakable+Tomorrow+Tomorrow+and+Tomorrow.htm
"Absolute Freedom" by FaithUnbreakable (Buffy/Methos; award winner for 2005): http://www.tthfanfic.org/Story-6104/FaithUnbreakable+Absolute+Freedom.htm
"The Buffy and Methos Chronicles" by Belladonna (decent Buffy/Methos, with friendships with Richie and Duncan): http://www.tthfanfic.org/Story-12257/Belladonna+The+Buffy+and+Methos+Chronicles.htm
"Life and Times of Dawn Summers, College Student" by Mei (actually a series of stories about Dawn's first semester of college in Seacouver, where she dates Richie Ryan and reluctantly introduces the immortals to her side of the 'weird' spectrum, slaying vampires and stopping apocalypses; now complete): http://www.tthfanfic.org/Story-1574/Mei+Life+and+Times+of+Dawn+Summers+College+Student.htm
"Slay Hard" by MMcGregor (Xander plays the Bruce Willis role when W&H office building is taken over by evil Immortals and their demon minions): http://www.tthfanfic.org/Story-6435-2/MMcGregor+Slay+Hard.htm
"A Watcher's Son" by AlecStar (primary crossover is with The Sentinel, but then Methos gets recruited in later chapters to become a Slayer Watcher, and things get even more interesting): http://www.booksandtales.com/fanfiction/awsindex.php
"Captive Love" by KaylaShay (Dawn/Methos; Dawn's romance with her ancient languages professor, Adam Pierson, takes an unexpected turn when someone from Methos' past decides to use her against him): http://www.tthfanfic.org/Story-9910/KaylaShay+Captive+Love.htm
"Adventures in Babysitting" by Demona (one-shot; Dawn gets kidnapped again and takes Buffy's new boyfriend Adam Pierson along for the ride): http://www.tthfanfic.org/Story-9978/Demona+Adventures+in+Babysitting.htm
(WIP) "Spike's Way" SERIES by OracleHolly (post-NFA for the most part, with second and longest story of this 4-part Spuffy series incomplete at 18 out of a possible 25 chapters since December 2007, but still worth re-reading): http://www.tthfanfic.org/Series-644 (or http://oracleholly.livejournal.com/tag/verse%3A%20spike%27s%20way, or http://www.bloodshedverse.com/stories.php?go=chapters&no=1023)
(WIP) "Puzzled" by LisaF (post-"Chosen" Dawn solves a linguistic puzzle that brings her to the attention of a number of experts, including 'Adam Pierson', who sets out to solve the puzzle of HER; hasn't been updated since December 2009, unfortunately, just when it was really getting going): http://www.tthfanfic.org/Story-19095/LisaF+Puzzled.htm
(WIP) "Looking for Acceptance" by Methos/Methos2523 (after Joyce's death in season 5, Buffy discovers that her birth father was actually supposed to be her mother's then-boyfriend Adam Pierson . . . who's alive and well and living in Seacouver, so she and Dawn decide to visit and introduce themselves; last updated July 2009, unfortunately [recently removed from TtH, but author intends to re-write and re-post on fanfiction.net, eventually]): first 5 of the 6 chapters so far can be read in cached copy at http://web.archive.org/web/20090708105828/http://www.tthfanfic.org/Story-13298/Methos+Looking+for+acceptance.htm, with chapter 6 at http://web.archive.org/web/20090727053702/http://www.tthfanfic.org/Story-13298-6/Methos+Looking+for+acceptance.htm.
House M.D.:
"Xander's New House" by DeepBlueJoy (one year after "Chosen", Xander moves to Princeton, just in time to enlist his surprise real bio-dad and some colleagues to help with the battle in L.A.): http://www.tthfanfic.org/Story-21362/DeepBlueJoy+Xander+s+New+House.htm
"Lost and Found" by NotJana (four years after "Chosen", and after yet another gut-wrenching bereavement, Buffy moves to Princeton to study physical therapy and ends up working on more than just House's sore leg; Buffy/House): http://www.tthfanfic.org/Story-16292/NotJana+Lost+and+Found.htm
"Sleeping In" SERIES by Mistral (visiting Dawn at Princeton University, Xander is struck with a strange sleeping malady that puzzles House and his team almost as much as do the extraordinary young women who gather around the sleeping man's bedside in the hospital): http://www.tthfanfic.org/Series-2941
"Who's Your Baby's Daddy?" SERIES by mmooch (as part of the Initiative's experimentation, Maggie Walsh had Buffy secretly impregnated with an illicit sperm sample, which requires Buffy and Giles to do some digging and traveling to meet the potential Dads and find out if any of them are likely to be actual decent father material; multiple crossovers, but one major -- and very angsty, in the end -- cross is with 'House'): http://www.tthfanfic.org/Series-1449
"The Ass" by Serenity (Buffy/House -- fluffy): http://www.tthfanfic.org/Story-14256/Serenity+The+Ass.htm
(WIP) "House's Key" by Sevangel (Dawn/House; abandoned just shy of completion in 2008, but still worth re-reading): http://www.tthfanfic.org/Story-10406/sevangel+House+s+Key.htm
'In Death' series:
"Little Old Ladies" by Vogonguard (J.D. Robb's police detective of the future meets an elderly Buffy Summers and Willow Rosenberg, in the course of investigating a new 'Bringer'-related homicide, and comes face to face with the world of the supernatural): http://www.tthfanfic.org/Story-14603/vogonguard+Little+Old+Ladies.htm
Leverage:
"Different Kinds of Knights" SERIES by JediButtercup ("The Soul Job", where Eliot enlists his team's aid in freeing twin brother Lindsey from his W&H contract during AtS season 5, and a collection of Buffy/Eliot follow-ups): http://www.tthfanfic.org/Series-2072
"The Lullaby Job" SERIES by toots (Dawn and Connor are re-born as Eliot's twin babies, raised by the 'Leverage' crew as an extended and uniquely functional little family; Eliot/Parker/Hardison, eventually): http://www.tthfanfic.org/Series-2280
"The Council Job" by toots (Connor is Eliot's brother -- sort of! -- and comes to Eliot and his crew for help when Dawn's latest kidnapper turns out to be human): http://www.tthfanfic.org/Story-20559-6/toots+The+Council+Job.htm
"Convergence" SERIES by txfantasystar (Eliot is Lindsey, reformed, and 8 years later Angel comes back into his life, asking for help from Eliot and his team): http://www.tthfanfic.org/Series-2023
Lois & Clark:
"Strong" by Shayne T (Lois becomes a Slayer just before she's reluctantly assigned a new partner, Clark Kent, and sent to investigate the Sunnydale sinkhole): http://www.tthfanfic.org/Story-13056/ShayneT+Strong.htm or http://www.lcfanfic.com/stories/2007/strong.txt
"California Cousin" by MarcusRowland (the Smallville sheriff asks Lois and Clark to look into the fate of her Sunnydale relatives the Harrises, post-'Chosen'): http://www.tthfanfic.org/Story-8333/MarcusRowland+California+Cousin.htm or http://archiveofourown.org/works/84037/chapters/113186
"Heard on High" by Jinni (amusing Willow/Clark one-shot): http://www.tthfanfic.org/Story-2421/Jinni+Heard+on+High.htm
Magnificent 7:
"Childhood Lost" SERIES by HiltonK (Xander is the son Ezra Standish never knew he'd fathered, until after the fall of Sunnydale): http://www.tthfanfic.org/Series-1404
Marvel Universe:
"Star Spangled Man" by Jaded (Buffy and Dawn grew up hearing their maternal grandmother's tales of her work with Captain America during WWII, only to meet up with the man himself and his new team after the battle with the Chitauri): http://www.tthfanfic.org/Story-27452/Jaded+Star+Spangled+Man.htm
"Personal Assistants, Super Heroes, & World Save-age" SERIES by Crunchysunrises (five times Buffy met Tony Stark, two times he offered her a job, and the one time she accepted -- culminated with an alternate ending to 3.01 "Anne", with a sequel focused on Pepper Potts' impressions of Buffy): http://www.tthfanfic.org/Series-3020
"The Captain America Type" and sequel "A Family Barbecue" by Brokenmimir (Buffy starts dating the cute neighbor who works out at her gym, and they discover they have even more in common than they thought: http://www.tthfanfic.org/Story-28872/brokenmimir+The+Captain+America+Type.htm and http://www.tthfanfic.org/Story-29292/brokenmimir+A+Family+Barbecue.htm
"It's an Acronym, Actually" SERIES by CaptainBoulanger (Coulson and Agent May from "Agents of S.H.I.E.L.D." cross paths with the Scoobies in Sunnydale, and their paths just keep crossing, to mutual benefit; additional minor cross with C.S. Lewis): http://www.tthfanfic.org/Series-2880
"Best Job Share Ever?" by JediButtercup (Buffy goes to work part-time for Nick Fury, as Tony Stark's personal assistant and wrangler): http://www.tthfanfic.org/Story-27812/jedibuttercup+Best+Job+Share+Ever.htm
"New Dawn" SERIES by ElzaCBoe (Dawn was created as Buffy's infant daughter in season 5, instead of as a teenaged sister, and years later Tony Stark is shocked to learn he fathered a child; badly in need of proof-reading, but still engaging): http://www.tthfanfic.org/Series-2769
"The Genius Curse" by DrakePendragon (Fred goes to work for Tony Stark instead of joining Angel and the rest at Wolfram & Hart, and that makes all the difference, you see): http://www.tthfanfic.org/Story-23715/DrakePendragon+The+Genius+Curse.htm
WIP "Fortune Days" by Jezaeiri (still being updated slowly, due to author's illness, but very much a living story; goes AU near the end of season 2, with Joyce's death at the hands of Angelus and Buffy's discovery -- AFTER going postal on Angelus, Spike, and Dru -- that her real father is Tony Stark, currently missing in Afghanistan): http://www.tthfanfic.org/Story-27630/jezaeiri+Fortune+Days.htm
WIP "Buffy's Hammer" by Becuzitswrong (stalled at 10 chapters since April 2010, but very enjoyable; at the end of season 5, Buffy's jump into the portal brings her out of a very different doorway in to the Baxter Building in a distant universe, where her Troll Hammer has merged with the powers of Mjolnir): http://www.tthfanfic.org/Story-15272/becuzitswrong+Buffy+s+Hammer.htm
"Enigma" SERIES by Batzulger (femslash; Buffy's leap into the portal at the end of season 5 lands her in the Marvel 'verse, where she becomes part of the superhero crowd and She-Hulk's girlfriend): http://www.tthfanfic.org/Series-1982
M*A*S*H:
"Shoveling" by PaBurke (retired and widowered Dr. Hawkeye Pierce gets drawn into the lives of his next-door neighbors in Cleveland, who happen to be a bunch of Slayers and Scoobies; 100 chapters of wonderful, touching story-telling, with some of Hawkeye's old Army friends also lending aid and comfort to the Slayers' cause): http://www.tthfanfic.org/Story-7661/PaBurke+Shoveling.htm
"A House by the Cove" by Freewrite (one-shot, very moving, though in need of much proof-reading; in 2004 Buffy and Dawn leave the Slaying world behind in order to reconnect with their maternal grandparents in Maine -- Hawkeye and Margaret Houlihan Pierce): http://www.tthfanfic.org/Story-7113/Freewrite+A+house+by+the+Cove.htm
Miles Vorkosigan 'verse:
"The Vor Slayer" by Vogonguard (Miles' daughter Helen is called as a Slayer, uncle Ivan actually turns out to be quite handy in the end): http://www.tthfanfic.org/Story-7765/vogonguard+The+Vor+Slayer.htm.
Sequel to Don Sample's short fic "With a Star": http://www.tthfanfic.org/Story-2251/DonSample+With+a+Star.htm
"The Taura-Tara Nexus" by Keswindhover (Sergeant Taura gets some unexpected ghostly help as she nears the end of her too-short life): http://www.tthfanfic.org/Story-11046/Keswindhover+The+Taura-Tara+Nexus.htm
N.C.I.S.:
"Little Brother" by NotJana (Xander is Abby's half-brother, but hasn't had much contact with her in recent years, so post-"Chosen" his female friends talk him into paying her a visit, leading to some close brushes with the Slayers' world on the part of various NCIS team members): http://www.tthfanfic.org/Story-19827/NotJana+Little+Brother.htm
"Chaos Theory" by Rainne (Kate/Gibbs, and eventual surprise NCIS agent pairing for Buffy; a magical accident in England causes a rift in space-time in D.C., and Kate Todd finds herself back in NCIS headquarters with no idea that she's been dead for two years; Buffy and Kate become friends and co-workers, and they help each other through some heavy emotional work): http://www.tthfanfic.org/Story-15667/Rainne+Chaos+Theory.htm
"Who's Your Baby's Daddy?" SERIES by mmooch (As part of the Initiative's experimentation, Maggie Walsh has Buffy secretly impregnated with an illicit sperm sample, which requires Buffy and Giles to do some digging and traveling to meet the potential Dads and find out if any of them are likely to be actual decent father material; multiple crossovers, but one major --and less angsty -- cross is with NCIS): http://www.tthfanfic.org/Series-1449
"Pigtails and Tweed" by Samarkand (Giles/Abby, and the two can get more than a little kinky in their bedroom antics at times): http://www.tthfanfic.org/Story-20313/Samarkand+Pigtails+and+Tweed.htm
"A Little DiNozzo" by toots (Buffy uses Tony's anonymous sperm donation to get pregnant, and then has to track him down six years later in order to get a transfusion to save her son's life): http://www.tthfanfic.org/Story-19445/toots+A+Little+DiNozzo.htm
(WIP) "Bring Up Your Dead" SERIES by grundy (first story is complete, and second story -- detailing just how Ziva's cousin Willow was involved in Ari and Caitlin both still being alive and together after all these years -- is a WIP): 1) http://www.tthfanfic.org/Story-27882/grundy+Bring+Up+Your+Dead.htm and 2) http://www.tthfanfic.org/Story-27943/grundy+Before+Twilight.htm.
(WIP) "Dawn's NCIS" SERIES by Sevangel (Dawn is Kelly Gibbs): http://www.tthfanfic.org/Series-1381
Numb3rs:
"Mathematics and Magic" SERIES by JessRS (Buffy/Charlie friendship, with something more; Buffy saves young Charlie from a vampire during her summer in L.A. after "Becoming", and things go AU from there): http://www.tthfanfic.org/Series-1194
"In Another Life" SERIES by Lyl (Willow/Don; amnesiac Willow, post-series): http://www.tthfanfic.org/Series-1492
Pitch Black/Chronicles of Riddick:
"Just the Way He Likes It" by Jedibuttercup (SHORT-ish fic, Riddick/Buffy): http://www.tthfanfic.org/Story-24081/jedibuttercup+Just+The+Way+He+Likes+It.htm
"The Primitive Side" SERIES by Jedibuttercup (series of short fics, pre-Riddick/Buffy): http://archiveofourown.org/series/1499 or http://www.tthfanfic.org/Series-48
"The (Real) Chronicles of Riddick" by msgordo (one-shot crack!fic, with Dawn and Conner joining Riddick and Kyra in their battle against the Necros, just for s**ts and giggles): http://www.tthfanfic.org/Story-7057/msgordo+The+Real+Chronicles+of+Riddick.htm
"The Restless Chronicles" by Cjsplace (Buffy/Riddick): http://www.tthfanfic.org/Story-8295/cjsplace+The+Restless+Chronicles.htm
Riverworld:
"Violence and Variations" SERIES by Kerrykhat (series of short fics, with a really intriguing Buffy/Burton thread running through, based on the 2nd miniseries where Peter Winger played 19th century explorer and author Sir Richard Burton): http://www.tthfanfic.org/Series-2348
Roswell:
"BtVS/Roswell" SERIES by Aesop (Liz is called as Slayer and Spike becomes her Watcher/trainer, as I recall -- very good): http://www.tthfanfic.org/Series-62 or http://www.tthfanfic.org/AuthorStories-2418/aesop2.htm (final story "Once Burned" is only posted on fanfiction.net: http://www.fanfiction.net/s/2094218/1/Once_Burned)
"A Matter of Trust" by Jinni (Willow-centric; Willow and AI gang rescue Michael Guerin from W&H): http://www.tthfanfic.org/Story-3199/Jinni+A+Matter+of+Trust.htm
"Goodbye and Hello" by Duchess (Xander-centric; Max goes off to Antar with Tess, and Xander drives to Roswell instead of Oxnard, where he ends up becoming a permanent part of the group; had remained technically unfinished at the end of chapter 19 for several years, though it felt pretty done, but author started updating again on 6/1013, with some promising new twists): http://www.tthfanfic.org/Story-9257/Duchess+Goodbye+and+Hello.htm
Sherlock:
"The Myffy Chronicles" SERIES by Jaded (Buffy/Mycroft! 13 stories, totaling under 22,000 words total; surprisingly engaging romance, including Dawn's eventual, unorthodox love connection): http://www.tthfanfic.org/Series-2495
Smallville:
"Smallville Glory" by ShayneT (Buffy and co. come to Smallville seeking someone strong enough to fight off the Hellgod Glory; Lex Luthor becomes intrigued by the potential of magic, and Willow discovers that Kryptonite can boost her power): http://www.tthfanfic.org/Story-21319/ShayneT+Smallville+Glory.htm
"Dawn's Fine" by Abra/Abra de Winter (Dawn/Brainiac; Brainiac/Prof. Milton Fine based his human form on a long-dead minor poet, and is intrigued when new student Dawn Summers reacts so strongly to him): http://www.tthfanfic.org/Story-8931/Abra+Dawn+s+Fine.htm (also on other sites, including http://buffy.adultfanfiction.net/story.php?no=600005331,http://archive2.livejournal.com/12828.html, and http://www.fanfiction.net/s/2880861/1/Dawns_Fine)
"The Date" SERIES by LastScorpion (Clark/Dawn, eventual Lex/Buffy; written in early season 2 of SV and season 7 of BtVS, so goes very AU for both series; Dawn and Clark go on a first date at the end of their freshman year at Metropolis University, which actually turns into a double date with Buffy and Lex, followed by major slayage, followed by Buffy 'outing' Superman as Clark Kent to Lex, and that's just the first story in the series!): http://www.tthfanfic.org/Series-1006 or http://archiveofourown.org/series/1481 (see also prequel and sequel chapters in "What Child is This"/"Kent Family Secret": http://archiveofourown.org/works/112992/chapters/157271, or https://www.fanfiction.net/s/1176995/1/What-Child-is-This and https://www.fanfiction.net/s/1183406/1/Kent-Family-Secret)
"World of Perpetual Wednesday, World without Superman" by LastScorpion (in an AU version of "The Date" series universe, where Dawn turned down Clark's first and only date invitation, Dr. Dawn Summers lets Superman talk her into sending him across space and back in time, and then finds herself in an AU version of her own Sunnydale where Buffy is alone, along with two different versions of Lex Luthor): http://www.tthfanfic.org/Story-6161/LastScorpion+World+of+Perpetual+Wednesday+World+w+o+Superman.htm, or http://archiveofourown.org/works/134412/chapters/192329
"Crossed Boundaries" SERIES by courderouge2006 (Clark/Buffy; after the angsty end of SV season 8 Clark comes to Cleveland, doing the 'lone vigilante' thing, and crosses paths with someone who's surprisingly like him): 1) https://www.fanfiction.net/s/5890666/1/Crossed-Boundaries; 2) https://www.fanfiction.net/s/5892969/1/You-Can-Take-the-Slayer-out-of-the-City; 3) https://www.fanfiction.net/s/5900157/1/Meet-the-Family-The-WHOLE-Family
"Small Towns and Hell Mouths" SERIES by courderouge2006 (Clark/Chloe, Buffy/Spike; BtVS late season 7 meets SV early season 5): 1) https://www.fanfiction.net/s/3126945/1/Small-Towns-and-Hell-Mouths; 2) https://www.fanfiction.net/s/3162200/1/Raising-Hell-Down-on-the-Farm
"Nighthawks" by SpaceAnJL (very funny short fic from 2002, set in an AU Smallville future, in which a Lex Luthor who knows his best friend is a flying alien walks into a bar and meets Spike and John Constantine, so they can drown their relationship sorrows together, and then hit Vegas . . . and Ethan Rayne; implied Chloe/Lex and Spike/Buffy, with a brief Constantine/Zatanna fling): http://www.tthfanfic.org/Story-28301/SpaceAnJL+Nighthawks.htm
"Memory" by nowhereman (Clark and Chloe visit Smallville on a Torch-related inquiry, and Clark gets hit by the 'Tabula Rasa' spell along with the Scoobies in "The Magic Box"): http://www.tthfanfic.org/Story-21815/nowhereman+Memory.htm, or https://www.fanfiction.net/s/5833118/1/Memory
"Where the Sun Don't Shine" by nowhereman (16-year-old Clark feels compelled to help when he hears of L.A.'s plight in AtS season 4, and so impresses Faith during the battle against the Beast that she and Willow ask him to accompany them to Sunnydale, to help out with the First; EXCELLENT story, worth savoring and re-reading): http://www.tthfanfic.org/Story-31045/nowhereman+Where+the+Sun+don+t+Shine.htm, or https://www.fanfiction.net/s/11162118/1/Where-the-Sun-don-t-Shine
"A Strange Meeting Place" SERIES by Chunk127/Chunkman (Clark/Buffy; needs more proof-reading, but definitely re-readable; Clark meets Buffy in Heaven when he dies from a gunshot wound in season 4 of SV, and they bond deeply before Willow resurrects Buffy and Jor-El restores Clark; over a year later, Clark hears that Sunnydale's being evacuated and runs there to help, on the off-chance that 'Buffy Summers' wasn't just a dream as everyone else insists; the final battle of Sunnydale goes somewhat differently with Clark on hand to help, and the sequel story has many more SV/BtVS pairings coming about): http://www.tthfanfic.org/Series-2534 or http://www.fanfiction.net/s/7722111/1/A-Strange-Meeting-Place (see also sequel chapters: http://www.fanfiction.net/s/7900552/1/Weddings-Phantoms-and-Men-in-Tights and http://www.fanfiction.net/s/8785369/1/A-Doomed-Wedding)
"Aliens, Mutants, and Demons" SERIES by BlueGold (SV/X-Men/BtVS cross, with only the 3rd and final story bringing in BtVS; Clark and Lex get together early in SV's timeline, and that makes a world of difference for everyone, including most of the misguided 'meteor mutants'): http://www.tthfanfic.org/Series-696
"Wish" by meridian_rose (While subbing for another Vengeance Demon with a different clientele, late-season-6 Anyanka offers early season 2 Lionel Luthor a wish; Lionel's wish undoes his blindness but messes everything else up, and in desperation he turns to his new reality's Chloe Sullivan to make a corrective wish): http://archiveofourown.org/works/325845 or http://www.fanfiction.net/s/7768156/1/Wish
link to 'Stargate'-related BtVS crossover fanfic faves and recs
Star Trek (TNG):
"The Way It Should Have Been" by Burmafrdnow (Q gets bored and decides to make it possible for Buffy to summon assistance from the crew of Picard's Enterprise, including a bunch of Klingons eager to practice their skills on some demon armies): http://www.tthfanfic.org/Story-24950/burmafrdnow+The+way+it+should+have+been.htm
"Legend" by ShayneT (Buffy's cryotank and the Buffybot are both recovered by Data when breaking out of Kivas Fadjol's collection, and the Federation wants to put Buffy on trial, at the demand of the Cardassians, because she's an inspiration to the Bajorans; Meanwhile, Spike's working for Section 31!): http://www.tthfanfic.org/Story-24717/ShayneT+Legend.htm
Star Trek (2009) or TOS:
"Terms of Enlistment" by Crunchysunrises (young officer Christopher Pike meets a bartender with the historically rare name of 'Buffy Summers' and ends up trying to recruit her . . . for the good of Starfleet, and not at all because he wants to have lots of sex with her! Really!): http://www.tthfanfic.org/Story-28199/Crunchysunrises+Terms+of+Enlistment.htm
"But Never Broken" SERIES by grundy (Faith winds up on Nero's ship, in a universe and timeline far from her own; 11 very short fics and a couple of drabbles): http://www.tthfanfic.org/Series-1963
"Fish Climbing Trees" SERIES by Polgara (Buffy/Bones): http://www.tthfanfic.org/Series-2642
"Bound in Story" SERIES by MochasNMayhem [formerly 'Koohii Cafe'] (Buffy & Kirk friendship; at the end of the original 5-year mission, a restless Captain Kirk finds an irresistible mystery in an antique trunk filled with weapons, crosses, and holy water, along with a chance to retrieve Buffy from the demon dimension she'd been trapped in since the destruction of Sunnydale; 26 chapters in all, only the first 19 of which were posted on TtH): http://archiveofourown.org/series/301023 [see also http://www.tthfanfic.org/Story-31227/MochasNMayhem+Bound+in+Story.htm for first 19 chapters]
Terra Nova:
"Dancing With Dinosaurs" SERIES by JediButtercup (Commander Taylor is surprised to find his "Auntie Liz" arriving with the latest migration, and not looking a day older than when he knew her as a boy; first story is complete, but second is a WIP) http://www.tthfanfic.org/Series-2502 or http://archiveofourown.org/series/16965
The Sentinel:
"A Watcher's Son" by AlecStar (primary crossover is with The Sentinel, with Rupert Giles turning out to be Blair's unknown father in the latter part of season five of BtVS, but then Methos gets recruited in later, post-"Chosen" chapters to become a Slayer Watcher, and things get even more interesting): http://www.booksandtales.com/fanfiction/awsindex.php
"Not a Dream, Fairy Tale, or Imaginary Story" by Batzulger (primarily a "Grimm"/BtVS crossover epic, with a secondary cross with "The Sentinel" in the form of a now Guide-less Jim Ellison, and a minor cross with "Fringe"; many years post-Chosen, Buffy and Dawn move from Cleveland to Portland, where Dawn teaches at a local university while Buffy works as a homicide detective, coming to terms with the heretofore largely unknown world of Wesen and Grimms and partnering with another recent transfer from Cascade PD named Jim Ellison; when the Norse Gods start working some major world-ending mischief in the Portland area, Buffy has to use all the available resources of Slayers, Watchers, Grimm, Sentinel, Wesen allies, and one reluctant Chaos Mage, in order to thwart their plans; no pairings at all other than those in "Grimm" canon, but good detective and adventure story-telling): http://www.tthfanfic.org/Story-29246/batzulger+Not+a+Dream+Fairy+Tale+or+Imaginary+Story.htm
"The Kin Series" by litgal (Blair has a relatively minor role in the two main stories, which focus on Angel becoming Xander's guardian in High School and then his lover in L.A.): http://www.tthfanfic.org/Series-1350 (or http://litgal.brinkster.net/Kin/Bumbling.htm and http://litgal.brinkster.net/Kin/Soul1.htm)
"Protecting the Light" by K-Lyn (Faith runs off to Cascade instead of L.A. after the body-swap in BtVS season 4): http://www.wolfpanther.com/stories/protecting.html
[sequel story is crossover between TS and First Wave, "Conquering the Spirit World" (the aliens target Blair , and Cade Foster comes to Cascade to enlist his help): http://www.wolfpanther.com/stories/conquering.html
"Of Shadows and Demons" by Mackie (BtVS/TS cross):
http://100megsfree3.com/fauxpaws08/mackie/shadows1.html
http://100megsfree3.com/fauxpaws08/mackie/demons2.html
Follow-up to "Of Shadows and Demons" by Mackie: http://100megsfree3.com/fauxpaws08/mackie/consume.html ("Interlude: Consumed by the Fire")
The Vampire Diaries:
"Sassy" by Echo (delightfully snarky and sexy Damon/Dawn, set early 2nd season for TVD): http://www.tthfanfic.org/Story-23417/echo+Sassy.htm
"And After the Storm" by Ava (one-shot -- so far! -- where Buffy gets stuck in a different dimension, apparently devoid of the supernatural and anyone she knows from back home, until she looks up her mother's family in Virginia, the Lockwoods of Mystic Falls; too bad she didn't know she'd inherited that pesky werewolf curse until it was too late): http://www.tthfanfic.org/Story-26928/Ava+After+the+Storm.htm
"Trouble Ahead" by Azure (Buffy is Jenna's younger sister and therefore aunt to Elena, and Damon becomes fascinated by her when she comes to visit in TVD season one; see also the sequel of sorts, "Enigma of an Aunt"): http://www.tthfanfic.org/Story-27009/Azure+Trouble+Ahead.htm and http://www.tthfanfic.org/Story-27043/Azure+Enigma+of+an+Aunt.htm
"Many Possible Vampire Husbands of Buffy Summers" by hellbells (multi-cross, desperately in need of proof-reading like all of this author's work; Buffy becomes immortal, marries Damon Salvatore, and in the second half of the story they end up aiding River Tam during the Firefly episode "Objects in Space"): http://www.tthfanfic.org/Story-27869/hellbells+Many+possible+vampire+husbands+of+Buffy+Summer.htm
"Family Matters" by hellbells (Buffy/Damon; cute short-fic, desperately in need of proof-reading, with sequel "Then They Were Two"): http://www.tthfanfic.org/Story-25697/hellbells+Family+Matters.htm and http://www.tthfanfic.org/Story-27887/hellbells+Then+they+were+two.htm
Tom Clancy's 'Rainbow Six':
"Rainbow Over Sunnydale" SERIES by JoeB (when the Initiative goes AWOL and tries to destroy the world, President Jack Ryan tasks Rainbow to defend the Hellmouth; additional major crossovers with "The Mummy" and "Charmed" in later stories, as well as "Die Hard" and "The New Avengers"): http://www.tthfanfic.org/Series-883
The West Wing:
"Potential" SERIES by kurttrout (2 short fics, exploring the idea of Helen Santos as a former Potential Slayer who's recruited to help train and support newly Called slayers in the Houston area while her husband's still in Congress, and who puts Buffy on her personal staff during the Santos presidential campaign, giving Josh some serious concern about what the three blondes -- Helen, Buffy, and Donna Moss -- get up to at times): http://www.tthfanfic.org/Series-2542
True Blood:
"New Dimension, Same Worries" SERIES by Polgara (3 short fics, in which Buffy deals with being stuck in a different dimension where snarky vampires STILL want to flirt with her): http://www.tthfanfic.org/Series-730
"Run" by FaithUnbreakable (goes AU for Buffy during "Earshot", leaving a telepathic Buffy on the run and meeting up with Eric at an opportune moment): http://www.tthfanfic.org/Story-18690/FaithUnbreakable+Run.htm (see also latest follow-up "A Thousand More", in which Buffy and Godric return to Eric after restoring Godric's will to unlive: http://www.tthfanfic.org/Story-28784-11/FaithUnbreakable+Wishlist+2012.htm, followed by 'coda' fic, "Flesh and Blood", in which Angel and Willow find a surprise when they visit Fangtasia on unrelated business, 20 years after Buffy's supposed death: http://www.tthfanfic.org/Story-23837-6/FaithUnbreakable+Wishlist+2010.htm)
"The Cure for Boredom" by SweetChi (Buffy/Eric; Buffy is bored after "Chosen", but an unexpected trip to the 'True Blood' dimension may be just what she needs; had been stalled at 43 chapters since June 2012, but chapter 44 was added Sept. 2013): http://www.tthfanfic.org/Story-24723-43/SweetChi+The+Cure+for+Boredom.htm
Underworld:
"Opposites Attract and All That Jazz" SERIES by houses (Lucian was delivered to his lawyers for treatment at the end of the first Underworld movie, and Fred discovers him when reviewing her new department's records at the start of AtS season 5): http://www.tthfanfic.org/Series-25
"Underpants World" by echo (Tara ended up in Michael and Selene's world, where Kraven thought it would be a good idea to steal her pants): http://www.tthfanfic.org/Story-6461/echo+Underpants+World.htm
"The Other Side" by oxnate (Xander dresses as an American Death Dealer for Halloween, and remains transformed after the spell is broken, leading to a very different outcome for the next few months of season 2 and a different side of the Yellow Crayon Speech; minor cross with "Highlander" only in research on Dark Quickenings near the end): http://www.tthfanfic.org/Story-28433/Oxnate+The+Other+Side.htm
(WIP) "Armistice" by JoeB (on the run with Selene from Vampire vengeance after the first movie, Michael is advised by his father Hank Summers to seek out his previously unknown half-sister, the Slayer, for help): http://www.tthfanfic.org/Story-14026/JoeB+Armistice.htm
"Savior" by Serenity (short-fic in which Buffy saves Lucian at the end of the first movie): http://www.tthfanfic.org/Story-17580/Serenity+Savior.htm
Xena: Warrior Princess:
"Thrust Back" SERIES by Jinni (Willow/Ares; very amusing, as I recall): http://www.tthfanfic.org/Series-262
"Not-So-Blithe Spirits" SERIES by RevDorothyL (Buffy is the latest re-birth of Xena's soul, with many other BtVS and AtS characters also turning out to have earlier incarnations in the Xenaverse and the world of H:tLJ): http://www.tthfanfic.org/Series-521