Quake III: Team Arena is the official add-on to Quake III: Arena.
It adds a lot of multiplayer game types: Harvester, Overload and One Flag, all focused on team play. There is a selection of new power-ups aimed at introducing a class-based structure similar to Team Fortress. Three new weapons are available: a nail gun, a chain gun and a proximity mine launcher. There is also a batch of new levels, and a few graphical and sonic tweaks like the inclusion of Doppler-shift effects when rockets streak past your head. And finally there is a set of one-use items like Kamikaze (kills you in a colossal explosion, taking out anyone unfortunate to be around) and Invulnerability, which freezes you in mid-air and surrounds you with a near-impenetrable shield.