HARRY POTTER
Wizards in love
"When I finished with Goblet of Fire, way back in July of 2000, I had certain very definite and (I thought) unshakable opinions about the HP universe. Draco was a slimy git, Tom Riddle was anything but a sympathetic character, Snape was interesting but still mostly evil, Lucius was not the sort to cross-dress, Narcissa was a vain idiot, and all the characters were heterosexual. My, how things have changed..." -- from A Newbie's Guide to the Harry Potter Fandom
The first major Harry Potter fan fiction novel was Harry Potter and the Paradigm of Uncertainty by Lori Summers. [add rec]
There's also A Sirius Affair, a prequel by Penny Linsenmayer and Carol Estes which relates how Sirius met his Muggle wife and other events later referred to in Paradigm of Uncertainty, and two sequels, The Show That Never Ends and the still-in-progress Hero With A Thousand Faces.
And then Cassandra Claire wrote her Draco trilogy...well, parts of it, anyway, and I enjoyed the series when I read it so I'm recommending it despite the fact that the fact that some of the dialogue and passages in her stories were quoted, adapted, and borrowed with minimal attribution (read: there was a big plagiarism scandal--Jintian has a discussion here for those who are interested). Anyway, regardless of who by (and obviously the author has good taste and a way with words of her own), the stories are well-written, funny, plot-twist-filled romances--even if I do often kind of wish it were a slash epic....
A Spirit of Brotherhood by torch -- I loved this story for the characterization and writing, although it felt like a prequel because it was slashy as hell but at the end there was definitely that sense of having been shown the loaded gun without the payoff--and I have nothing against pre-slash or nonexplicit stories, but the sheer amount of setup given the lack of follow-through could potentially annoy some readers. I still wouldn't have missed it, though. A skillful exploration of the relationships between Sirius Black, Remus Lupin, and Severus Snape.
Pretty much everything by the Lady of Shalott...
No Choice of Poisons by cmshaw -- With the exception of torch and shalott's work, this story probably made the greatest impression on me of any I have read in the fandom. [add rec] While you're there, also check out What Friends Are (not) For--Mosca said in her rec for this story that what she really liked about it was how realistic the teenagers were (and how hilarious it is), and I totally agree.
A Quaint Notion by Helen -- This ends on a cliffhanger and I really wish she'd written the sequel, but it's Ron/Draco and it's Helen and it's all good.
Like A Good Book by Kyra Cullinan --
Where do the Children Play? by Cairnsy
Footnotes by Jennifer-Oksana -- Snape and Hermione talk in the kitchens. A very insightful take on the characters and their relationship, and it's PG-13 which is just a relief to me.
They Always Say, You Can't Go To Hogwarts Again by Loligo -- Remus Lupin. Vignette. Angst. Come on, what are you waiting for?
Waltz for the Moon by Naraku -- Everyone recs this
Whoopee Cushion by Seeker -- Because even the broomstick loved Snape...
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