Dumbledore is the only confirmed one, but others are often speculated, such as remus because lycanthropy can come off in some way as an analogy for being gay,
Well its an analogy for AIDS which is associated with homosexuality. But Remus is in love with Tonks anyway. And, obviously, straight people can get AIDS too.
^^^^that is true, but again that's just how alot of people speculate, along with the actor being told to play a "gay junkie" and that he thought remus was gay until he found out about tonks.