Free and open source voxel art tools - editor, thumbnailer and format
a parametric 3D CAD modeler
3D fractal rendering software
Character animation system for games and simulations.
Pencil2D is a cross-platform animation/drawing application.
projectM, a MilkDrop compatible opensource music visualizer
kicad 3D is aimed to add 3D realistic feature on kicad pcb CAD
Audio & Video Producer Suite
Cross-platform application for digital painting
C/C++ library to add light and intuitive GUI to OpenGL and DX programs
Superseded by the official Gimp release: http://www.gimp.org/downloads