libtwo - All-purpose c++ app prototyping library, focused towards live graphical apps and games
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Grit Game Engine - The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua.
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
MOS - Lightweight game engine.
ZBrush - ZBrush is a digital sculpting and painting software solution.