Incest and impregnation/pregnancy are my biggest ones. I don't mind lolis myself as long as they are of legal age (and I say this because there are people out there in real world that are in their 20s or 30s but for whatever reason they just look extremely young, it's not their fault, and should that be a stoppage to finding happiness and love?), but my loli preference is oppai loli, haha. I also don't mind futanari but only if it's futanari/female action, but it's still not particularly any content I go looking for.
It's mostly the extreme stuff like Netorare, cuckold, hotwifing, sharing, bestiality etc etc that I steer away from, I want none of that