Pygame - Pygame is a set of Python modules designed for writing games.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Unity - The multiplatform game creation tools for everyone.
Sculptris - Sculptris: Enter a world of digital art without barriers.
Grit Game Engine - The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua.
ZBrush - ZBrush is a digital sculpting and painting software solution.