The Joker- The Dark Knight
Agent Smith- The Matrix Trilogy
The Boss and young Ocelot- Metal Gear Solid 3
Anakin/Darth Vader and Palpatine- Star Wars
Xehanort and Vanitas- Kingdom Hearts
Paul Heyman- WWE
Damaras- Kaizoku Sentai Gokaiger
Kefka Palazzo- Final Fantasy VI
Count Olaf- A Series of Unfortunate Events
Dr. Evil- Austin Powers
Bania- Seinfeld
Clubber Lang- Rocky III
Hades- Disney's Hercules
Can't think of others at the moment.