Major Antagonists:
* Magneto: The most iconic X-Men villain, Magneto is a powerful mutant with the ability to manipulate magnetism. He believes that mutants are superior to humans and should rule the world, often clashing with Professor X's dream of peaceful coexistence.
* Apocalypse: A powerful, ancient mutant with the ability to absorb the powers of others, Apocalypse seeks to cleanse the world and create a new order with himself as its ruler.
* Sabertooth: A savage and brutal mutant with enhanced senses, superhuman strength, and regenerative abilities, Sabertooth is a relentless predator and a sworn enemy of Wolverine.
* Mystique: A master of shapeshifting and deception, Mystique is a skilled spy and assassin who often operates in the shadows. She has a complex relationship with the X-Men, sometimes acting as an ally and other times as a ruthless enemy.
* The Brotherhood of Mutants: A group of mutants led by Magneto who believes that humans are the enemy and mutants must rule. This group has included numerous members throughout the years, including Toad, Pyro, and Blob.
Other Notable Adversaries:
* Mr. Sinister: A brilliant but ruthless geneticist obsessed with manipulating mutant evolution.
* The Juggernaut: An unstoppable force of nature with immense strength and invulnerability.
* The Sentinels: Powerful robots designed to hunt and destroy mutants.
* The Hellfire Club: An exclusive and powerful organization that seeks to control mutant powers for their own ends.
* William Stryker: A military leader who believes mutants are a threat to humanity and seeks to eliminate them.
Organizations:
* AIM (Advanced Idea Mechanics): A scientific organization that often dabbles in dangerous technology and has clashed with the X-Men on several occasions.
* Hydra: A global terrorist organization with a history of seeking to control mutant powers.
* The Purifiers: A fanatical group of humans who believe that mutants are a plague upon the world.
It's important to note that the X-Men have faced many other adversaries throughout their long history, but these are some of the most notable and recurring foes. The X-Men's enemies reflect the complex themes of prejudice, fear, and the struggle for equality that are woven throughout the franchise.