Blender - Blender is the open source, cross platform suite of tools for 3D creation.
HeroMachine - Create your own super-hero, sci-fi, or fantasy character sketch
ZBrush - ZBrush is a digital sculpting and painting software solution.
Avatar Maker - Create your own avatar online
DAZ 3D - Daz 3D, 3D Models, 3D Animation, 3D Software
The Character Creator - aims to provide a fun and easy way to help you find a look for your characters.