Benny's 3D Engine List

All engines are PC-based, DOS, with C/C++ source code and executable.

The original code isn't mine, I reused code. Sometimes my additions are minor (like adding SVGA, mouse, keyboard handler), sometimes they are more advanced changes (like adding music, physics, collision detection.) Generally the code is for Watcom, DJGPP and/or sometimes TurboC.
For a much more extensive list, visit The 3D Engines List.