Molly Hooper hasn't been given much in the way of character development by the writers of Sherlock. Fortunately, fandom is making efforts to fill in the gaps.
Three takes on our favorite pathologist:
it's time for a few small repairs, she said by
fialleril Post-The Great Game, Molly takes off her mask. Lovely story of the way Molly asserts herself, bit by bit.
Dear Jim by
furius A very subtle, quietly unsettling fic, with details that only become clear upon a second reading. One of the most intriguing backstories for Molly that I've seen.
The Number Is by
randombattlecry Molly and Jim, and a conversation that shows that they're neither of them quite sane. Dark and delicious.