The fandoms I signed up for were Bandom-Fall Out Boy (Pete/Patrick), Bandom-Panic! at the Disco (Ryan/Anyone), Bandom-My Chemical Romance (Anyone/Anyone), American Idol S7 (David/David) and American Idol S8 (Kris/Adam).
I... tend to be pretty OTPish, (except where noted with an Anyone, apparently MCR defies specific pairings for me, and, well, I adore Ryan from Panic), but so long as you don't put half my pairing with someone else (especially Pete/Patrick, I'm having a ridiculous amount of feels for them these days), I'll probably be ok going outside those pairings.
I mainly read slash, but I also enjoy het, femslash and occasionally gen (I'm a hopeless romantic so plotty gen tends not to do it for me).
Things that I love in fandom stories:
-Girls (gender swap or always-girls tropes are included)
-Harlequin-esque storylines (see note re: being a hopeless romantic)
-Werewolves/fantasy/sci fi AUs
-Actually, AUs in general
-BDSM, D/s and other power dynamics
Things I'm hesitant about:
-Cheating (I can deal with it, if it's actually dealt with in a meaningful way)
-Straight up PWPs (if I'm going to enjoy a PWP, it generally has power dynamics at play)
-Steampunk (I just... never really got into steampunk?)
-Sexualized cannibalism (I feel ridiculous writing this down as my only no-go, because it doesn't seem the kind of thing you'd spring as a surprise on someone, but man, the one time I ran across it in fandom traumatized me so bad I just have to make sure. Sorry!)
If you want help finding something I'd like, I bookmark everything I finish and, if I particularly liked it, I'll tag it as a rec. You can find my recs on Pinboard.