Hello there!
First things first, thank you so much for offering my pairing! While I may have more ideas, or more specific ideas, for certain pairs, please believe me when I say I love and would enjoy fic for all of them. If I didn't adore them, I wouldn't have requested them after all! :D Also it is worth noting that I have the most to say about Rung/Whirl because they actually have some content for me to reflect on. I have less to say about the others precisely because there is just short of nothing out there, not because I like them less. I know some of my prompts might not be to your taste, please know that I would much prefer you write a fic you are passionate about than one that rigidly but unenthusiastically follows my ideas. Writing fic you're proud of is half the fun of an exchange!
Rung/Whirl (MTMTE)
This pair is already not very popular, but when you add the fact that I only ship this in AUs where Whirl is not, and has never been, Rung’s patient (patient/therapist romance makes me really uncomfortable, even if the attraction is unrequited) it's basically impossible to find fic for it.
I really like hurt/comfort in general but with this pairing my h/c cravings are through the roof. There is plenty of room for angst, especially when it comes to commiserating about being victimised by the functionalists. Whirl was forced to work for them and disfigured to assure compliance. Rung was experimented on, probably tortured, and ultimately declared functionless by them. They both have emotional and physical scars from their ordeals. I would really like to see them negotiating physical intimacy in this light. Trying to figure out how to kiss and hold hands in light of Whirl's empurata. Negotiating the minefield of triggers that Rung's torture left him with. Rung wants to communicate and be respectful of Whirl’s boundaries. Whirl is uncomfortable about the fact that he’s uncomfortable with some things and as per usual reacts by getting angry but Rung is very patient and never pressures him and they find ways to be intimate that both of them are happy with.
Also it should be known that Rung wump is... kinda my greatest weakness. I'd love a story where Rung gets captured by hostile mechs and beaten up/tortured, and Whirl storms their ship to save him. And afterwards Whirl is all growly and possessive/protective of Rung. Or maybe Rung sees someone who had a hand in his torture during the functionalist era and has a flashback, and Whirl is... not great at emotional comfort but more than able and willing to kill the mech in revenge for what they did to Rung. Alternatively Whirl could see someone who tormented him in prison and Rung has to try to keep him from killing the mech right then and there, as well as comfort a bot who refuses to admit any emotional vulnerability.
But my Rung/Whirl ideas are not limited to angst! I'd love to see happy/fluffy getting-together fic. In an AU where they are not patient and therapist, what brings them together? (One specific scenario I've thought of is one where Whirl is on the LL and Ultra Magnus wants to make him start seeing Rung to do his court-mandated therapy. Whirl finds out that therapists can’t treat people they’ve had relationships with, so he goes on a mission to seduce whoever this “Rung” guy is before Ultra Magnus can schedule an appointment. But then he actually meets Rung and oh no he’s hot. Rung, meanwhile, is confused but really flattered and has no idea that Whirl is the same guy Ultra Magnus wants him to see professionally. Another scenario could be a pre-war deal where the Senate tasks Whirl with keeping an eye on Rung to make sure he doesn't use his functionless status to start a rebellion. Rung probably notices his not so stealthy tail and offers him energon and a sympathetic ear. Whirl and he discuss the perils of being functionalist pawns and they find themselves getting more and more attached to each other.
I could also dig an ensemble of other characters on the LL looking at Whirl and Rung and being like “what a weird couple” but at the same time realising that they work really well together. Rung helps Whirl stay in control of his anger and Whirl keeps Rung from constantly overthinking and panicking about things. Rung is very affectionate and supportive and Whirl acts like he’s ~too cool to care~ but really he cares so much. Maybe members of the crew are gathering at Swerves and throwing out theories about how they could have gotten together and what the pit the sex is like?
Just some general dynamics I like about Rung/Whirl that you could incorporate: size difference, nice guy/jerk guy pairing, both of them are not used to affection, smart guy/tough guy pairing, both of them are super hot aesthetically. You can make any of these prompts as nsfw as u want to. If you are into making porn I prefer tactile and plug and play. Also, if you are okay with noncanon pronouns, I like "she" for Whirl and singular "they" for Rung (I use canon pronouns here just for familiarity)!
Larry/Jackie (The Neighbors)
My beloved alien nerds! They may not be popular, but at least they got tons of cute moments in canon. I'd really love to see early relationship fic for them, since they have such an interesting history (also one that, admittedly, hits a whole bunch of my idfic buttons). What was it like for a freedom fighter to realize she is the soulmate of one of the dictators she is trying to destroy? Did she try to deny it or immediately switch sides? How did Jackie go from a rebel to a 50s-ish housewife (I'd rather it be happily than unhappily)? I love weird courtship and mating ritual stuff, so including those would be especially awesome! Another story I'd love is something that covers them being jealous/possessive about one another, especially if it showcases their role change (Jackie being possessive on Zavron when Larry is the more desirable one, Larry being possessive on Earth when Jackie is the more desirable one). I'd also love to get domestic Larry/Jackie fic, like their early days of settling into earth, weird alien courtship practices, trying to figure out how to decorate a human house, etc. I'm also a sucker for inter-culture friendships, so feel free to include the Weavers.
And by the by, if you are comfortable with writing something NSFW, Larry/Jackie happens to hit so many of my kinks it's embarrassing. These include: A Head of The Household /housewife style D/s dynamic, major power discrepancies, subs comforting Doms when their overinflated egos get bruised, F/M mpreg, pairings with different levels of attractiveness (Jackie being the hot one by Earth terms and Larry being the hot one by Zavronian ones is a bonus), foe yay (considering Jackie used to be a freedom fighter), mating seasons, and emotional/psychic instead of physical sex. So if you're okay with getting kinky I would love to read some Larry/Jackie smut.
Violet/Artemis (Crossover)
If you matched me on this, my rarest of ships, it would truly be something! I'm not even sure how I started shipping this, but mysterious origins aside I think they would make a magnificent pair of dark-haired genius inventors. I'd love to see absolutely anything with Violet and Artemis together! I think they would have a very interesting dynamic and would challenge each other intellectually and emotionally. Their lived experiences have many similarities but also significant differences. Artemis usually gets himself into trouble though his own boredom and aspiration, relying on Butler and his wits to get him through. Violet, meanwhile, wants nothing more than peace and safety for her family but she is drawn into danger and forced to rely on her inventive mind for survival through forces beyond her control.
Some specific ideas: Violet and Artemis grow up to become secret agents and have to work with or even against each other on a mission. Artemis becomes tangled up with VFD through his more illicit dealings. Violet gets tangled up with fairies through her natural curiosity and thirst for knowledge. The Baudelaire and Fowl families have been friendly for generations and Violet's search for allies and companions leads her to Artemis. Violet begins working (secretly, under a pseudonym) as a freelance creator of gadgets and weapons, and an impressed Artemis vows to uncover her identity and hire her himself.
Also here are some of my general "likes":
Domesticity, worldbuilding, humor (particularly dark and dry), mixes of angst/humor/fluff, unusual things seen in mundane light and vice versa, D/s dynamics that don't involve sex, atmospheric fic, existential/high angst themes, snarky dialogue
...as well as some general "dislikes":
Violence towards animals, (unasked for) cross-overs, bashing of characters