Starhawk

Starhawk, aka Stakar of the House of Ogord, is responsible for the creation of the original Guardians of the Galaxy, the team that operated in the 31st century of one timeline of the Marvel Universe (the same team that Yondu was a member of).

Starhawk is the child of Marvel Comics heroes Quasar and Kismet. He was kidnapped by a villain as an infant and cursed to an endless cycle of possessing his own infant self and reliving his life. The curse has allowed him to accrue a vast amount of knowledge, including knowledge of alternate timelines, which he used to form the Guardians of the Galaxy.

Starhawk was once a pacificist and archeologist, but his cursed life turned him into an antihero. Starhawk gained his powers after being merged with a woman named Aleta. The two were separated then married and had children. Unfortunately, the two were then merged again and must constantly battle for control of their shared body.

Martyr

Phyla-Vell is the artificially created "daughter" of the original Captain Marvel. Mar-Vell, and "sister" of Mar-Vell's son and inheritor of the Captain Marvel legacy, Genis-Vell.

Phyla-Vell originally laid claim to the title of Captain Marvel, but Genis-Vell refused to abdicate the role. During the events of Annihilation, Phyla-Vell became the new Quasar, which is when she joined with Star-Lord's Guardians of the Galaxy. Later, she became the avatar of Oblivion and took the new name, Martyr.

Martyr is also a lesbian and has a romantic relationship with the telepath Moondragon, herself a member of the Guardians of the Galaxy, though mostly in a support role.

Major Victory

Major Victory is Vance Astro, the 31st-century incarnation of Vance Astrovik, the New Warriors and Avengers member known as Justice with the mutant gift of psychokinesis.

This version of Vance changed his last name to Astro after touring with the U.S. Air Force. He then joined a special space mission to colonize Centauri-IV and was placed into suspended animation for the trip.

In the 31st century, Vance Astro wakes and takes on the persona of Major Victory and finds the shield of the long-dead Captain America. Major Victory wielded the shield as a member of the Guardians of the Galaxy alongside Starhawk and Yondu.

Major Victory falls for Aleta while she's still married to Starhawk, but the romance is ruined when Starhawk and Aleta merge together again, prompting Starhawk's expulsion from the Guardians of the Galaxy.

Angela

Angela was the firstborn child of Odin and Freyja, and therefore the sister of Thor and Loki. She had been all but forgotten after the Queen of the Angels kidnapped and then tried to murder her as an infant and Odin, in retributed, cut the realm of Heven from the World Tree, Yggdrasil.

When disposing of the infant's body, the Queen of Angels' handmaiden discovered the child was alive. The handmaiden chose to hide the child and raise her as one fo the Angels. While Angela was always mocked for lacking wings, she proved her worth and was named Leader of the Hunt.

The time-travel that took place during the Age of Ultron event weakened the barrier that separated Heven from the other nine realms and Angela was pulled through. The transition left Angela disoriented, but she encountered the Guardians of the Galaxy and chose to join the group.

Adam Warlock

While Adam Warlock himself hasn't appeared in the flesh in the Marvel Cinematic Universe, there was a pretty significant Easter egg reference to him in Guardians of the Galaxy in the form of his cocoon be kept in the Collector's lair.

Adam Warlock is a messianic, godlike figure in the Marvel Universe and has been a major player in Marvel's cosmic events for decades, including The Infinity Gauntlet. He is constantly in conflict with a religious organization called the Universal Church of Truth and their leader, Magus. The tragic part is the Magus is actually Adam Warlock himself returned from the future.

Adam Warlock was a major supporter of Star-Lord forming the modern Guardians of the Galaxy team. Warlock considered the move necessary for the preservation of the universe, especially after the spacetime continuum was damaged during the Annihilation event and Adam needed assistance in repairing the damage. This ultimately ended with Adam becoming Magus.