Porn contains: amateur anal, big ass anal, first time anal, hard and rough sex, big natural tits, big boobs, big booty, amateur couple, doggystyle, anal plug, butt plug.
Porn contains: submissive slut, slut, slut wife, domination, face slapping, deepthroat, extreme deepthroat, hard and rough sex, picking up stranger, facial.
Porn contains: hard and rough sex, hard fast fuck, doggystyle, bondage, bdsm, best friends fuck, cheating, cheating wife, redhead, cum in mouth, cum inside.
I'm sure it's better to search for porn with tags rather than categories. Usually authors specify a few general categories and lots and lots of qualifying tags. Here's a list of the most popular amateur porn tags. Not enough? Below is a link to all the tags used on Hobby.porn.