3D Engine c++
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
Short C++/Java/C#/Python benchmark
3D .NET engine for Windows, Linux, Mac
XNA based game engine completely written in c#
A cross-platform game framework based on OpenGL and GObject.
https://github.com/horde3d/Horde3D
A continuation of the abandoned Tao Framework project.
Multi-Language Wrapper Collection for the Irrlicht Engine