So i've always wanted to become part of a game development team, like an underground one for maybe a mod of some sort. However, the only langguage i am somewhat familiar to is C, thus far. Are there any mods or third party games i can help program for with my knowledge of C? Or is it ALL C++?
You've skipped right over the Game Development forum on C Board, to ask a question about using C, for writing game code.
You need to go to the game development forum(s), both here, and elsewhere, for an authoritative answer.
My opinion is yes, it's largely C++, but I'm not a game developer, either.