Alcoholic ex-citizens of the Luna Colonies who were shipped to New York and have gone crazy from agoraphobia after being raised in pressure domes. They skin people alive in hopes of using said skin to cover their own fragile complexions.

The citizens on Starkesboro, Massachusetts, who were transformed by, and in the servitude of Dredmund Druid. Rescued by Captain America, Dr. Druid, Wolverine and the Werewolf.

The armed forces of the Upper and Lower Kingdom.

A security strikeforce team of young mutants lead by Moonstar in the Age of X. The Moonstar Cadre consists largely of members that are normally recognised as New Mutants. They were sent to capture Legacy & later used by the mysterious X to assassinate Magneto.

A semi-humanoid alien race with green skin and hair. A Morani crew once attacked The Watcher.

Outcasts from society, the Morlocks were a community of mutants who lived in tunnels beneath New York City and its vicinity.

Monstrous humanoids that live underground in The Time Machine by H. G. Wells.

Morning Glories is a team consisting of the students attending the Morning Glory Academy.

A group of Cernunnos-worshipping assassins. They were founded by Morris Major, an agent from an evil version of Great Britain.

A group of miniature-sized Fables who form their own mounted police force and most commonly work in the espionage field for larger Fables.

The Moyl Men are a group of small aliens who eat foreskin.

Mister Somebody Enterprises.

Ms. Magnificent And Her Pretty Boys is a gang of body builders.

The M-Squad was a group of human scientists that used technology to try to capture mutants.

John Constantine's old band.

The Mud Brothers (sometimes Mudd) are two ogre-like brothers who aid The Goon when he needs some extra muscle.

A cannibalistic tribe of warriors that stalk the Marshlands of Northeastern Keshan. They are fearsome and blood-hungry savages that smear their bodies with garish earthen paints and don terrifying clay war-masks to raid their neighboring villages. Only the mystic might of the Kaintiba-Mah and the swordsmanship of Conan of Cimmeria backed by the Iron Damsels could break their power and end their reign of terror.

The first four Clayfaces who banded together to battle Batman.

The Muir island X-men are a group of mutants who lived on Muir Island and formed a new X-Men team after the original team was presumed dead. They are also known as the Muir Islanders.

Incorporeal parasites composed solely of emotional energy born from the astral plane of existence.

Citizens of Munchkin Country, the eastern quadrant of the Land of Oz.

Patrolling the Streets of Philadelphia.

A team made up by Ammo to cause the collapse of society

The Muppets when they were very small children. They make their dreams come true.

A deadly carnival of Frankenstein.

A team of six elite Black Ops soldiers, led by Colonel Jacob Kane.

The goddesses of inspiration from Greek mythology.

Former members of Magneto's second incarnation of the Brotherhood of Evil Mutants. Shocker, Burner, Lifter, Peeper and Slither reunited as the Mutant Force. The often served as of Professor Powers incarnation of the Evil Empire. The group know as Mutant Force often team with Mad Dog.

The new Stryfe group

Gathered from the corners of the Earth by Stryfe and manipulated to fight for a cause he himself did not believe in, the MLF were terrorist pawns fighting to end humanity's dominance over mutants.

The M.R.D. (Mutant Response Division) are a militant unit that hunt down mutants.

Group of minions to the evil Mumm-Ra stranded with the Thundercats on Third-Earth.

Mutant Underground was founded by Professor Xavier to handle secret missions.

Led by the Light, The Mutant Underground of Singapore is an organization dedicated to conquering humanity and establishing mutant rule. They are great admirers of fellow mutant Magneto.