Genres (this list is probably incomplete, but it's a good start):

[list][*]Low Fantasy
[*]High Fantasy
[*]Modern Fantasy
[*]Sci-Fi
[*]Slice of Life
[*]Mystery
[*]Post-Apocalyptic 
[*]Steampunk
[*]Cyberpunk
[*]Superhero
[*]Academy/School (possible overlap with Slice of Life)[/list]

General tags:

[list][*]Original
[*]Derivative (to be applied to roleplays based on a pre-existing universe, like Star Wars, Harry Potter or the Vampire Diaries; there's probably a better word for this)
[*]1x1
[*](Large, Small) Group
[*]Nation 
[*]Tabletop
[*]Mature (containing themes or content less suitable for minors)
[*]Open
[*]Recruiting
[*]Closed (to be changed at will by the GM)[/list]