Unity - The multiplatform game creation tools for everyone.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Struckd - 3D Game Creator - Struckd is the next-generation gaming platform for user created content where people of all ages...
MakeHuman - MakeHuman is a free, open source, interactive modeling tool for creating custom 3D human characters.
Reality Factory - Reality Factory is a free suite of game development tools for building 3D games.
Bforartists - Bforartists is a fork of Blender.