Reunion Series: Ultron, Ahriman Loki, Red Skull, Winter Warrior, General Ross, Hatred, Justin Momo, Whip Tip, Destroyer, Ice King Laufey, Dr. Zola, Mandarin, aldridge Kirian, Cold-blooded, Malekis, Agrim, Alexander Pierce, Crossbones, Baron, Dr. Destroyer, Man Adult.

The villains in X-Men: Wan Ciwang, Mr. Ginger, Red Queen, White Queen, Black Queen, Hei Di, Witch, Azar, william stryker and Apocalypse.

Villains in Spider-Man: Venom, New Venom, Serum, Slaughterhouse, Female Slaughter, Despise, Scarlet Spider Generation I, Scarlet Spider Generation II, Professor Lizard, doctor octopus, Electricity, Green Devil, Vulture, Doctor Doom.

Other villains: Thanos, Kang the Conqueror, Jinhe, Dark Lord, Silver Surfer, N 'Astir H.

Rebel organizations: Ten Commandments, Zetari Army, Pioneer Science and Technology, Hand in Hand, Hydra, Sinister Six, Wan Ciwang Brotherhood, Cosmic God, Dark Avengers, Hellfire Club.

Source: sogou encyclopedia. I changed a little myself.