Mr. Teatime is really good.

Does Rust count as a villain? Can't say he brings much good to the series as a person!

Dios. What a dark figure saddled with a dark fate. He's basically cursed to live the same life over and over again, no wonder he's insane. I think the implication is that he created all the Djelibeybian gods, and the reason these gods existed at all were because they were the ones that were always recreated by Dios. His staff of a snake eating its own tail is apt.

The Patrician - his speech in Guard! Guards was fantastic.

I really like Cosmo Lavish. I think that is primarily due to the fact that I find the eyebrow machine very funny.

I'd go with Fate; something about the patient malice of a god trying to win a bet just feels right.

The Hiver hands down Like... basically an entity of nundualistic evolution through the ages. Tiffany turned manic when possessed and the little "help me" is also relatable

I think Mr Tulip wins for me. The art stuff, the -ing and his "drug" habit slay me. And I kind of feel bad for him despite his psychopathic murderous tendencies.

Carcer, he really stands out as truly evil to me.
Vorbis as a close second.