Title Character
Clark Kent/Kal/El/Superman
Supporting Cast
Lois Lane | Jimmy Olsen | Ambush Bug | Steel
Villains
A-L (Alexander "Lex" Luthor, Bizarro, Vril Dox/Brainiac, Cyborg-Superman, Darkseid, Doomsday, Lobo) | M-Z (Mongul, Superboy-Prime) | Phantom Zone Criminals (General Zod)
Spin-Offs
Supergirl (Kara Zor-El/Linda Danvers/Supergirl, Supporting Cast, Rogues Gallery) | Power Girl | Superboy (Conner Kent/Kon-El, Jonathan "Jon" Samuel Kent, Supporting Cast, Rogues Gallery) | Legion Of Superheroes (The Founders, Silver Age, Bronze Age, Five Years Later, Postboot, Threeboot, Retroboot, Rebirth, Other Heroes, The Fatal Five, The Legion of Supervillains, Other Villains, Supporting Cast)

Being the Long Runner that it is, Superman has faced a wide variety of enemies.