Shapefest - A massive library of 3D shapes for everything!
Unity - The multiplatform game creation tools for everyone.
PixCap - A browser-based 3D animation editor and assets library.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Wannathis - 3d illustrations and freebies
Blender - Blender is the open source, cross platform suite of tools for 3D creation.