Superman has many enimies. He has to deal with them on a daily basis. If he weren't so powerful, he probably wouldn't still be alive!
Lex Luthor, Brainiac, Doomsday, Darkseid, Bizarro, Composite Superman,
Eradicator, Faora, General Zod, Jax-Ur, Livewire, Metallo, Mr. Mxyzptlk, Parasite, Prankster, Toyman, Kru-El, Lashina, Zaora and the Intergang which consisted of mainly Bruno Mannheim.