It's hard to pick just 10 but after thinking long and hard, I think I'd go with these:
Peter Quill (from Marvel's Guardians of the Galaxy)
Gamora (from Marvel's Guardians of the Galaxy)
Drax (from Marvel's Guardians of the Galaxy)
Groot (from Marvel's Guardians of the Galaxy)
Rocket (from Marvel's Guardians of the Galaxy)
Mantis (from Marvel's Guardians of the Galaxy)
Nikki Gold (from Marvel's Guardians of the Galaxy)
Cosmo (from Marvel's Guardians of the Galaxy)
Lady Hellbender (from Marvel's Guardians of the Galaxy)
Ko-Rel (from Marvel's Guardians of the Galaxy)
Like I said 10 is really difficult, I had to leave out some other favorites. There are so many great characters in video games.