There's a few of those on the site, for all of those genres and usually most contain multiple genres.
If you haven't roleplayed for awhile, I suggest the Free roleplay section, where post length and quality are pretty lax. A lot of new ideas and topics stream through as well, so you have a pick of different ideas and new topics to join and try out. A lot of posters are kind of put off when a large chunk of story has already been posted, but don't let that happen! Just PM the GM of the topic and see if they're open to new blood! ^-^