Shapefest - A massive library of 3D shapes for everything!
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
PixCap - A browser-based 3D animation editor and assets library.
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
Wannathis - 3d illustrations and freebies
ZBrush - ZBrush is a digital sculpting and painting software solution.