Gimp - like photoshop
Inkscape - like illustrator
Kuler - color
Audacity - audio
VLC - video
P5.js - coding
Processing - coding
Arduino - coding
PixelMath - image processing
Google SketchUp - 3d design
Google SketchUp - 3d design
OpenSCAD - 3d design
Blender - 3d design / animation
MakerWare - 3d printing
Cura - 3d printing
Fusion 360 - 3d design