DC is a Quake clone created by Valve. It is extremely fun to play with lots of people, but has a mostly dead community.

CoF is a surprisingly well-made horror game. The story, although mysterious, manages to fit in nicely and the combat is alright.

CSCZ brings a campaign into the Counter-Strike series, and it does it fairly well. It has no plot, but has enhanced graphics, still great nonetheless.

CSNZ is a port of Counter-Strike Online to the West. It is well made and updated frequently with a lot of active players. The only downside is the p2w.

Although mostly taken as a joke by various people. Ricochet is crazy fun with lots of people.

Half-Life impacted gaming because of it's interesting story, amazing A.I., and it's realistic first-person perspective!

An amazing game from the '90s which continues to have large communities, updated servers, and creative mapmakers!