Sven Co-Op, Action Half-Life, Synergy, Obsidian Conflict, SourceForts, MINERVA, Riot Act, some parts of SMOD, and probably Black Mesa when it comes out (if ever).
Anybody play HL Blue Shift the one where your a security guard?
EVERYONE has that expansion.
Team Fortress, Counter Strike and anything valve related that isn't Half Life and Half Life 2 is either a mod by Valve itself or a fan made mod (Garry's Mod).
Yes, but TF2 is standalone. CSS and DoDS are standalone as well, they're just remakes of mods and TF2 is a sequel to a mod that was remade for HL.