Groups

Aliens and alien races in the Legion mythos. Major races (Dominators, Khunds, etc.) are listed as separate groups.

Artificial lifeforms robotic, organic, or similar—including artificial intelligences.

Artists, Entertainers, Journalists, Tour Guides, etc.

The Blackhawk Squadron was a paramilitary organization of pilots formed in the early days of World War II.

Living brains kept in globes, jars, or other containers.

A genetic engineering project headquartered in Metropolis.

The Challengers of the Unknown are a team of professional adventurers who regularly cheat death on their missions of discovery and exploration.

Creature Commandos are a team of monsters and freaks active during the Second World War, led by Lt. Shrieve.

Group of supervillains on Earth-Three; 

An insurgent group bent on conquering Earth and the United Planets.

DC Staffers inexplicably present in Legion adventures.

Incomplete group of criminals, assembled by Evillo and charged with evil energy.

Inimical alien race bent on domination of the universe. Their realm, the Dominion, is a frequent opponent of the United Planets.

Agents and leaders of the Earth government.

The Endless (Destiny, Death, Dream, Destruction, Desire, Despair, and Delirium) are a somewhat dysfunctional family of seven siblings.. The characters embody powerful forces or aspects of the DC Universe. They have existed since the dawn of time and are thought to be among the most powerful beings in the existence. They are distinct from and more powerful than most gods.

Family members of Legionnaires, including family members who later became Legionnaires in their own right.

The Fearsome Five are a team of ruthless super-villains who mostly battle the Teen Titans and the Outsiders. Their original membership included Doctor Light, Gizmo, Mammoth, Psimon, and Shimmer. They are extremely dangerous, although heavily prone to fighting amongst themselves and betraying each other.

A group of young New Gods from New Genesis who were on a mission to oppose Darkseid on Earth, and talked, dressed, and acted much like the flower children of the 1960s. In addition to the individual abilities and equipment of the members, the group can join together using the technology of a Mother Box to summon the powerful hero known as the Infinity-Man. The group travels by use of their Super-Cycle. The first issue of their title also introduced the Boom Tube.

The Freedom Fighters are a team of American super-heroes led by Uncle Sam. Originally they were the last heroes of Earth-X, where the Nazis had won World War II and taken over. They fought against tyranny and oppression in a completely authoritarian world.

The Global Guardians is a team of superheroes whose members hail from countries around the world.

Green Lantern, Green Arrow, and associated characters.

The Haunted Tank is a military tank crew led and commanded by then sergeant Jeb Stuart during World War II, and watched over by the ghost of Confederate General Jeb Stuart.

Assistants, usually unnamed, of a bad guy.

A group of heroes from the planet Lallor. All their powers derived from the same incident.

Heroes who are not included in any other group.

The Inferior Five are a parody superhero team created by writer E. Nelson Bridwell and artist Joe Orlando.

The characters are the children of members of a superhero team called the Freedom Brigade, a parody of the Justice League of America.

Espionage arm of the United Planets.

Hostile forces bent on conquest or plunder.

A 20th/21st century group of super-heroes. Appearances are only noted when they occur in Legion titles. No attempt is made to distinguish between alternate versions.

Militaristic alien race bent on conquering the galaxy. The Khund Empire is a frequent opponent of the United Planets.

Licensed Extra-Governmental Interstellar Operatives Network. A 20th/21st century analog of the Legion. Some members were ancestors of Legionnaires, some were from the same worlds, and some were actual past or future Legionnaires.

A group of super-powered individuals from Dryad. The Legion rescued the population of Dryad when their sun went nova; these six (children at the time) mistakenly believed that the Legion had caused the disaster. They were recruited by The Dark Man as agents to destroy the Legion.

Training institute for super-powered individuals. Some graduates earn Legion membership.

A sub-team of the Legion whose expertise in espionage is called upon when needed. Chameleon Boy is the permanent leader of the Squad, while other permanent members include Invisible Kid, Phantom Girl, and Shrinking Violet. Other Legionnaires are drafted from time to time as their abilities are needed.

Organization of super-powered pets of Legionnaires.

A group of super-powered children on the planet Quarantine. Garridan Ranzz was the son of Garth Ranzz and Imra Ardeen Ranzz. Kent Shakespeare, Celeste Rockfish, and Mara Williams were (unofficial) adult assistants to the Li'l Legion.

A ragtag group of military men in World War II, featured in Our Fighting Forces comic.

The Metal Men are liquid metal robots made from various elements each with almost limitless shape shifting abilities. They were created by the brilliant robotics expert and Elementical genius Dr. William Magus.

The Monster Society of Evil is a supervillain team led by Mister Mind against their hated enemy, Captain Marvel. The Monster Society consists of every major enemy Captain Marvel had ever faced.

The New Gods came into existence after the world of the old gods, the gods of classical mythology, was destroyed during Ragnarok. The world of these known deities was split and became two separate planets, forever linked, but utterly different. One is called New Genesis and the other is Apokolips.

The Gods of Olympus are an extra-dimensional race of beings who were worshipped as gods during the Ancient Greece. They no longer seek worshippers today, but they are still worshipped by the Amazons and Atlanteans.

The Omega Men are a team of extraterrestrial superheroes. They are active in the Vega planetary system, where they rebel against the tyrannical rule of the Citadel.

President Leland McCauley founded the Oversight Watch to be Earth's front line post-human defenders after the dissolution of the Legion. The Watch draws its members from the Legion (M'onel) and the Workforce (Repulse), along with new recruits from around the United Planets. 

Inhabitants of the twilight dimension used for punishment of criminals on Krypton.

A 20th century government-sanctioned group of paranormals.Timber Wolf (adult) (Glorithverse) worked with them during his sojourn in the 20th century.

Six individuals given powers by the Hutchings Institute to act as a new group of American heroes. The experiments meant to give them powers ended up creating Starman (Will Payton), who became their enemy.

An inimical, grenocidal alien race from the Progeny Galaxy. Inspired by their radical belief that they are the "perfect" life form, the Progeny hunt down and destroy entire species that theyb deem "variants/"

A 21st century group of super-powered young people. Appearances are only noted when they occur in Legion titles. No attempt is made to distinguish between alternate versions.

Members of any rebel/resistance group fighting an illegitimate government/occupation/etc.

Not to be confused with R.E.B.E.L.S.

A 30th century group of ring-powered superheroes sponsored by the Global Grace Foundation.

An alternate-universe band of super-powered teens who, under the care of a tiger named Romo, struggle to avoid the authorities in 23rd century Metropolis.

Scientists and/or medical personnel of all types, good or evil.

The Sea Devils are a team of deep sea adventurers and environmentalists.

The Seven Soldiers of Victory (also known as the Law's Legionnaires) is DC Comics' second super-hero team, following the Justice Society of America. Like the Justice Society, the membership of the Seven Soldiers is drawn from DC's anthology comics: The Vigilante (from Action Comics); the Crimson Avenger (from Detective Comics); the Green Arrow and Speedy (from More Fun Comics); the Shining Knight (from Adventure Comics); and the Star-Spangled Kid and Stripesy (from Star-Spangled Comics).

Unlike most superhero teams, this one includes two sidekicks, Speedy and Stripesy, as members (Stripesy is a rarity, an adult sidekick to a "kid" lead character). The Crimson Avenger's sidekick Wing also takes part in the team's adventures, and is in every other way an "eighth Soldier," but is never considered an "official" member. All but one of its members (the Shining Knight, a time-displaced Arthurian knight who rides a winged horse and uses an enchanted sword and suit of armor) are non-powered humans who rely on conventional weapons or training in place of superhuman abilities.

(Yeah, there were eight of them. Crimson Avenger's sidekick, Wing, was Chinese...thus, in the 1940s he didn't count. Score another point for casual racism.)

Residents of Smallville, usually in Superboy's time.

Characters from Star Trek continuities.

Superman and associated characters.

A 20th/21st century group of super-powered young people. Appearances are only noted when they occur in Legion titles. No attempt is made to distinguish between alternate versions.

The Time Masters are a team of time-traveling adventurers lead by Rip Hunter. Their mission is to explore time and solve problems affecting the timestream. They would later be replaced by Rip Hunter's second team, the Linear Men. 

Officials, agents, and/or leaders of the interstellar government (excluding Science Police and Interstellar Counterintelligence Corps).

A Daxamite-supremacy terrorist group

A superhero group formed & controlled by Leland McCauley, rivals to the Legion. (Earth-247 continuity).