The G3D Innovation Engine, by Morgan McGuire — 3D Player Models for Quake 2

"The G3D Innovation Engine is a commercial-grade C++ 3D engine available as Open Source. G3D supports hardware accelerated real-time rendering, off-line rendering like ray tracing, and general purpose computation on GPUs. Its design emphasizes rapid prototyping and innovation, particularly of rendering and game algorithms. G3D provides a set of routines and structures so common that they are needed in almost every graphics program. It makes low-level libraries like OpenGL, network sockets, and audio channels easier to use without limiting functionality or performance. G3D is a carefully designed, feature-rich base on which to prototype your 3D application. The contributors span the graphics industry. The engine is primarily maintained by Morgan McGuire, Zander Majercik, and Josef Spjut at NVIDIA, Corey Taylor, and Michael Mara at Stanford University & Oculus Research. It includes contributions from professional game developers, CAD and DCC developers, students, industry researchers, and professors."

The Coven: Disposable Heroes, Deadlode 2, and more Quake II Total Conversion Mods

The Coven was an independent computer games developer with its roots in the Doom and Quake communities. Originally founded by John "Gestalt" Bye in late 1996, The Coven worked on a free Doom II add-on before moving on to Quake and going commercial in the summer of 1997. The Coven was closed in the winter of 1999, and all their work is now available for free.