well here are the types of rps that I like and do both sexual and non sexual (also I'm bi-sexual so I'll leave that to you)
some insest
Brother/sister
Son/mother
(btw don't ask it's just fun to rp with)

mosters and humans yay
Hunter/Vampire
Werewolf/human
Vampire/human
hunter/werewolf

school subjects XD
Student/Teacher
Nerd/cheerleader
Principal/student
School nurse/paitent

casual subjects
Best friends
arch-rivals
dorm mates

Strange subjects
Human/Furry (not full furry, well maybe but not full animal)
Furry/furry (again no animalistic characters)

My Rpcs
Greed (horn dog)
Innocence (summisive, sweet, kind,loveing)
Idolotry (heartless demon)
Hitman (mature, inteligent, lonely, trained killer)
and anything else I can make on the spot