Who are some of your favorite fictional villains?

Some of my favorites:

Batman's villains (so many great ones)
Lelouch's corrupt family from Code Geass
Lex Luthor from Superman
Skeletor from He-Man
Magneto and Mystique from X-Men
Giovanni from Pokemon
Fisher Biskit from Littlest Pet Shop
Mr. Clipboard from Foodfight!
Duke of Weselton from Frozen
Shredder from TMNT
Doc Ock from Spider-Man
Mayor Humdinger from Paw Patrol
Eva and the Petbuster from Puppy in My Pocket