Avogadro - Avogadro is a free, fantastically easy to use molecule editor.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
UCSF Chimera - UCSF Chimera is a highly extensible program for interactive visualization and analysis of molecular...
MakeHuman - MakeHuman is a free, open source, interactive modeling tool for creating custom 3D human characters.
Jmol - Jmol is a free, open source molecule viewer for students, educators, and researchers in chemistry...
Bforartists - Bforartists is a fork of Blender.