Many kudos to the /a/ board on Plus4chan for happily offering up some especially juicy badfic for killing. I don't know if I can burn through this entire block by myself (or want to), so I'm offering anyone experienced in the canon to take their pick. If not, I'll just grind through it bit by bit.

http://plus4chan.org/boards/a/res/58098.html - In which I ask an entire board of Avatar maniacs to toss me some fresh targets. The only one in this thread you can't pick...

http://cartoon.adultfanfiction.net/story.php?no=600040939 - Is this one, which I intend to make suffer. Firecest (that is, Fire Nation Royal Family incest) written pre-S3 by a bunch of teenagers RPing who have no idea how to roleplay the male gender.

Other highlights include...

http://avatarfanon.wikia.com/wiki/AvatarMysticForcePart1
http://avatarfanon.wikia.com/wiki/AvatarMysticForcePart2
http://avatarfanon.wikia.com/wiki/RangersGoneBad
http://avatarfanon.wikia.com/wiki/Kidnapped - Formatting and punctuation-less fic that appears to be an attempt at making Power Rangers out of the Gaang.

http://cartoon.adultfanfiction.net/story.php?no=600040755 - The title of this one is "Katara's guide on how to love a Bear." I don't think I can say much that can top that alone.