The Open Toolkit library is a fast, low-level C# wrapper for OpenGL
Opensource Created Custom Viewers For Virtual Worlds like SecondLife.
Vivid is a modern C++ 3D engine using OpenGL4+
realtime 3d surface rendering library
Educational framework for OpenGLES, OpenCL and OpenAL
Pear3DEngine is a modern and modular 3D development framework
A modern 3D App framework using OpenCL to render via raytracing