I use and recommend the following:
 | OpenSUSE. An open source Linux based Operating System | www.opensuse.org |
 | Blender. Open source 3D software. | www.blender.org |
 | GIMP. GNU Image Manipulation Program. Open source image manipulation and editor. | www.gimp.org |
 | Darktable. Open source photography and RAW processing software | www.darktable.org |
 | Inkscape. An open source vector and illustration program. | inkscape.org |
 | Audacity. Free image recording, editing, and processing software. | www.audacityteam.org |