To fans of Supernatural, "Team Free Will." Refers to the characters Sam and Dean Winchester and Castiel, the main badasses who fought against the destined apocalypse in the show's fifth season. Because
screw destiny, humanity can choose what kills 'em and it's not gonna be
Satan and dickish angels.
The vernacular arose when Dean sarcastically labeled the three of them in episode 5x13:
Dean: This is it.
Sam: This is what?
Dean: Team Free Will. One
ex-blood junkie, one dropout with 6 bucks to his name, and
Mr. Comatose over there.
Awesome.
Fandom quickly picked up the phrase as shorthand to refer to the three characters as a unit.