"Dumbledore's Army and the Year of Darkness" by thanfiction

http://www.fanfiction.net/s/4315906/1/Dumbledores_Army_and_the_Year_of_Darkness

I'm not really familiar with thanfiction's fandom history  but this is a pretty well-done fic with a fairly ardent fanbase. I usually try not to rec stuff that's already well-known unless I truly love it (like "My Immortal" or "Slytherin Spy") but I really quite enjoyed this and I figured, Why the hell not?

It's about what happened for the DA during year seven. Pretty enjoyable.

"The Strange Disappearance of SallyAnne Perks" by Paimpoint

http://www.fanfiction.net/s/6243892

I love when stories uses flaws in Jo's writing to create a whole story arc. The only complaint I have about this story is that the author TOLD us the timeline in author's notes instead of leaving it up to the reader with clues in the texts, but really, this is something y'all should check out.

Do you know what happened to Sally-Anne Perks? To quote:

There weren't many people left now. "Moon" "Nott" "Parkinson" then a pair of twin girls, "Patil" and "Patil" then "Perks, Sally-Anne" and then, at last - "Potter, Harry!" (Harry Potter and the Sorcerer's Stone, Chapter 7)

Ten minutes later, Professor Flitwick called, "Parkinson, Pansy - Patil, Padma - Patil, Parvati - Potter, Harry." (Harry Potter and the Order of the Phoenix, Chapter 31)

~At some point between September 1991 and the spring of 1996, Sally-Anne Perks left Hogwarts. Perhaps she dropped out of school. Perhaps she fell ill. Perhaps she died. Or maybe she just vanished...

"My Immortal" by XXXbloodyrists666XXX

I don't really need to talk about this story, I just wanted to post it because I genuinely love it. If I had to name my favorite fanfic, this would probably be it.

http://myimmortalrehost.webs.com/chapters122.htm 

"The Misadventures of Draco Malfoy, Ferret" by Saber ShadowKitten

Just ... read it.

http://www.fanfiction.net/s/2690275/1/The_Misadventures_of_Draco_Malfoy_Ferret

"Harry Potter and the Slytherin Spy" by Christine Morgan

What if there was another Hogwarts student in Little Whinging?

This fic, written/set right after Order of the Phoenix, is about Harry meeting a Slytherin girl and forming a friendship with her in his sixth year. It's fairly-straightforward and not excessively (wonderfully) violent at all. (Sarcasm.)

http://www.eskimo.com/~vecna/hp_spy_01.html

Morgan can imitate Rowling's writing style well, and there is something so satisfying about reading a fic you can confuse for the genuine article; especially when it gets to where Morgan is describing gruesome deaths in Rowling's simple, yet descriptive prose.

I'm not pretending this fic is without problems; it's focused on a female OC, which is a no-no to most in the fandom, though trust me when I say the writing is good enough you won't care. And there are a few canon things that would raise eyebrows - Kreacher's characterisation is all wrong in this fic, in my opinion, while I think Morgan's explanation of where Sirius was hiding during Harry's thirteenth summer is a brilliant twist. Morgan also abuses ellipses, and the ending seems a bit rushed and simplistic, but trust me when I say:
YOU SHOULD READ THIS.