5 Major Guardians Of The Galaxy Members We Didn't See In Vol. 2
WARNING: MAJOR SPOILERS AHEAD FOR GUARDIANS OF THE GALAXY VOL. 2! ONLY READ IF YOU WANT TO [...]
Vance Astro
Major Victory, AKA Vance Astro, was a leader of the original Guardians of the Galaxy. Astro carries a shield just like Captain America's, and he was a pivotal part of the team.
Astro didn't just lead the original team, but he became a vital part of the 2008 Guardians that are featured in the film. He fought alongside the likes of Star-Lord and Rocket, as well as Starhawk.
So, why wasn't Astro in the movie, alongside the others?
Unfortunately, Major Victory is considered a mutant. This means the rights to his character belong to 20th Century Fox, not Marvel Studios.

Cosmo The Spacedog
Fans already saw Cosmo in the first Guardians movie, and that was a major nod to the Dan Abnett comics. If you recall, in those books, Cosmo was the head of security on Knowhere, and became a major ally to the team.
With his inclusion in the first film, many believed he would appear in Vol. 2 as well. After all, Howard The Duck is much less important to the Guardians, and he got a spot in both movies.
When all was said and done, Cosmo only appeared as a still image in the final credits.

Quasar/Phyla-Vell
There are multiple iterations of Quasar throughout the comics, but Phyla-Vell is the version who traveled with the Guardians the most.
Phyla, daughter of Mar-Vell, was a team member in the 2008 version of the Guardians. She had inherited the Quantam Bands - which make her Quasar - before the run had began, but gives them back to Wendell Vaughn around issue #12. After losing the bands, and making a deal with a dragon, Phyla-Vell takes up the mantle of Martyr.
One of the character's biggest ties to the team was her relationship with Drax The Destroyer. In the comics, Phyla was in love with his daughter Moondragon.
The movies have taken a different approach with Drax, so the characters of Moondragon and Phyla-Vell would likely have different back-stories.

Bug
Bug was never a very vital member of the Guardians of the Galaxy, but he was a lot of fun to have around.
The character joined the team during Abnett's run, after the team suffered a minor break-up. When many members of the group went their separate ways, Rocket brought in some other folks to help fill in the gaps. Bug was one of these additions.
While he doesn't bring much to the table, Bug brings a lot humor into dark situations. With Rocket having a bit of a heartbreak at the end of Vol. 2, and Groot being fully-grown once again, the third movie could be in need of some other forms of comedic relief.

Nikki Gold
While Nikki Gold wasn't one of the very first Guardians, she joined up not long after they began. The team found her on an abandoned ship, floating outside her home planet of Mercury.
Nikki has remained an integral part of the Guardians of the Galaxy history since then, being involved in many of their major storylines.
With Starhawk, Aleta, Charlie-27, and Martinex showing up in Vol. 2, it was a little surprising not to see Nikki. Especially since the film featured Taserface, a character she had memorable battle with in the comics.
