Nuclear is a family of open source game engines written to be able to read most standard game formates such as BSP(Quake I, QuakeII, Quake III, and Half-Life) MDL, MD2, MD3, and many more.
QuakeII Weapons Facotry (THE Team fortress for QuakeII) meets Quake III Arena WFA. The engine is founded on Q2 GPL code, and uses the WFA media. Visit the main website for more details.