Um....okay lets see....
Teacher x student (yaoi)
Student x student (both yaoi and straight)
Human x demon (both)
Vampire x vampire hunter (yaoi)
Demon x exorcist(think Kekkaishi) (yaoi)
Neko x Neko (both)
Neko x Inu (both)
Forest god x human (yaoi)
I'm fairly open about pairings since the plot is what matters.