The Open Toolkit library is a fast, low-level C# wrapper for OpenGL
Vivid3D is an open-source 3D engine with powerful 2D UI.
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
2D Controls Library using OpenTK/GL (Linux)
3D .NET engine for Windows, Linux, Mac
Teleidoscope using USB camera
A class library to use conformal geometric algebra in C#
A continuation of the abandoned Tao Framework project.
OBJ Load & Display Library
Superseded by OpenTK: https://sourceforge.net/projects/opentk/