Porn contains: petite, point of view, amateur couple, long legs, eye contact, beautiful girl, my hot step sister, stepsister, long hair, small pussy, butt.
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.
