Depends how I'm feeling. Going over my favourites, I see;
Futa, ahegao, pregnant, monster girls, scat, guro, loli, traps, ballbusting, chubby, shota, pegging, femdom, incest(mom or sister), birthing, bondage, amputee, muscle, armpits, hairy crotch or armpits, glasses, urination, dark skin, etc.
Easier to say would be things I really don't like, and that'd have to be rape, ntr, and things like slutty girls. That's a REAL turnoff.
Can't find a picture with everything in it, but this is one of my favorite doujins of my favorite touhou characters, so I'll post a picture of it.