Free software list
All kinds of cool stuff. Includes the usual download-able programs, and online apps. Many of these I've personally tried, others are just very popular among other artists/coders/Creative People I vaguely know, so you can assume they're all safe.Let's go!
Digital Art
FireAlpaca, GIMP, Paint.Net, Medibang Paint Pro, SAI Paint Tool (30 day trial), ... DeviantArt MURO, EZgif.com3D
Sculptris, Blender, L3DT, Terragen Classic, Earth Sculptor... Three.js (kinda pushing the boundaries, but they do have an online tool where you can test stuff with 3D models, lighting, rotation etc)... Magica Voxel...Coding
Visual Studio, Notepad++...Fractal art
Sterling (old but may still float around), Apophysis, Incendia, Mandelbulb etcOther generator sites
Links to websites with different kinds of generation tools. You might find these useful in your world-building or whatever. They certainly inspired me - I first started playing with code so I could create generators too. :)Chaotic Shiny - so many fantasy text generators! They also have a little tool to make your own.
Seventh Sanctum - again, sooooo many text generators.Rinkworks - an incredibly complex name generator. You can tailor it in virtually any way.
Donjon - very interesting tools including world map and dungeon images. I've played with the Markov chain stuff, results are nice.Springhole - large variety of text generators and articles about story-writing.
Language (vocabulary) generator - like Rinkworks, it allows a great deal of customisation.
Polygon map generator - very impressive. I'm in awe at their coding skills....
3D map generation - you can't download the results, but still very interesting.Note: include skybox, texture generators? Lots of them about.
Misc
Odd stuff that can't be categorised.Voxelizer - online tool to change a normal 3D model into voxel blocks. The same website has some other neat tools too.
Handwriting generated by neural network - I find NNs fascinating and this online tool is no exception.Hex colour blender - could be useful when designing CSS colour schemes.