Evil things

[Estanesse]

The only Maia that we can say for sure were persuaded by Morgoth to his cause are, I think, Sauron and the Balrogs.

And of course Ossë

As for dragons and Vampires, it is hard to imagine that the Kelvar possesses such powers as the dragons have. Because when you look at Carcharoth, he had no special powers such as for instance Glaurung had.