Villains (or antagonists) are the characters in a story that oppose the protagonist(s) by having different or opposing ideas and views, they are often the conflict of the story. Villains can also be the own protagonists of a story. Over time there have been several bad-guys that have been recognized by readers for their skills and personalities. You can add any villain regardless of their gender or race.
Rules: As this is a list directed more towards classic literature, please do not add any books in the genres of modern YA, urban fantasy, teen fiction, etc. If a villain appears in a whole book series or trilogy, add the whole box set instead of adding each particular book. Thanks!