Houdini - Houdini covers all the major areas of 3D production, including:
DeleD CE - DeleD is a 3D modeler and level-editor combined into one.
Mixamo - A 3D character pipeline built for game devs
3DTin - 3DTin is a browser based 3D modelling tool.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Pmx Editor - PMX Editor is for editing 3D model data to be used in MikuMiku Dance.