Blofeld.

The Donald Pleasance one - the others can't compare.

The Mighty Monarch from The Venture Bros.

Lorne Malvo... Jehova... John Kreese has recently gotten my attention.

Darth Maul, criminally underused - him looming over all three prequel episodes would have been straight cash - Anakin killed him in Ep 3 to take his place as the Emperor's apprentice in my CANON fanfic thank you

The joker in the dark knight

Lady DeWinter

I dont think i have one

Side Show Bob. No, actually, Hank Scorpio.

Aku.

Tom Ripley.