I've heard of one or two others, but I don't know them off the top of my head.

As for "why not"--I'm guessing it's supply and demand. I noticed at the recent ATP there were a lot of character ads that specified they weren't interested in sex games. so I think the majority of players in DWRP aren't interested in sex games, and for those that are, probably most of them are already in Amat or Zodion.