I like reading, so I guess I'm fit to be a betareader. I would say that I probably notice things that other people usually don't notice, so maybe look for a second beta reader if you want to acquire my services. I really think that two sets of eyes are better than one. My expectations are that you expect a lot from yourself as well as expect from me too.
I will beta read from any fandom but, of course, that means I may be unfamiliar with a certain fandom. This is what you should expect depending on the type of media your fandom comes from (i.e. Books).
Anime: I've watched/seen a decent amount of anime, so chances are, unless it's a niche anime, I've heard about what you're writing.
Books: I've read a decent amount of books too, but since there are so many, I'll list the popular ones I've read: Percy Jackson, LotR, Narnia
Movies: I'll just watch the movie you're writing about, so don't worry, unless it's a terrible movie.
Cartoon: Please just direct me towards a wiki link about a cartoon because I may not know it.
Comics: I don't read comics, so...
Games: Just tell me which game and I'll research some lore.
TV Shows: I have not watched most of the popular TV Show fandoms on this website, however, that does not mean I don't watch TV Shows.