A few years ago I compiled a list of bad guy motivations. I’m now posting it here. Hope this helps others looking to write three dimensional villains!
Remember, writers, villains need to be just as well-rounded as protagonists. They need their own backstories and motivations. They cannot do bad things just for the sake of being bad.
Jafar from Aladdin
—For his third wish, Jafar wishes to be “an all-powerful genie!”
2. World Domination
Sauron from Lord of the Rings
—One ring to rule them all.
Voldemort from Harry Potter
—Not one, but seven horcruxes. He Who Must Not Be Named took extraordinary measures.
Regina/Evil Queen from ABC’s Once upon a Time
—Regina wants revenge against Snow White.
Guy of Gisborne from BBC’s Robin Hood
—Poor Guy can’t stand the idea of being poor.
6. Get the girl
Imhotep from The Mummy
—Imhotep killed the Pharaoh because he had the hots for his wife.
7. Prove themselves/A desire to be the best at something
James Moriarty from BBC’s Sherlock
—It’s about winning the game and proving that he’s better than Sherlock.
8. True belief that what they’re doing is right/will make the world a better place
Valentine from City of Bones
—For Valentine, the ends justify the means, even if he has to kill those in his path.
9. Mentally Insane
The Joker from The Dark Knight
—I miss Heath Ledger. Also, this is the trickiest kind of villain to do, so use sparingly.
Loki from Thor
—Loki is jealous of his older brother, Thor.
Magneto from X-Men
—Magneto believes that mutants are better than humans, so he persecutes the poor humans.
12. Greed/Wanting something so badly that you’re willing to do anything to get it
Lamia from Stardust
—In this case, the object of her desire is the heart of a star. Another example is Cruella De Vil from 101 Dalmatians, her motivation being a puppy fur coat.