I mostly use Gimp to edit my photos. It's free and easy to use. You can download it here
I use it for some of my fractal and mosaic remixes of my paintings.
There are dozens of tutorials on Youtube on how to use Gimp
A great sample library I use to find unique sounds for my music.
Ubuntu Studio Operating System
It's a fast, stable and FREE Linux based O.S. It comes with a whole bunch of great software for musical and visual artists.
Ardour - A DAW much like Ableton or Protools
Gimp - Mentioned above
Blender - 3D Images and Movies
Inkscape - Vector based graphics tool that rivals Adobe Illustrator
Openshot Video Editor
Krita- Illustation & Animation
OBS Studio - Live Streaming
and a lot more.
I use this print-on-demand service to make my clothing.