u/Anton-Denikin

For the 2d image one : https://tsargames.com/tools/image-pixelator

No login, backend or anything. Completely free just upload your image, (and mesh if doing 3d) and just edit to your own liking!

Great for Ps1 games, NS64 style games, Ps2 Style games, etc.

https://tsargames.com/tools/retro-3d-texture-editor

Basically put your finished model and texture here, then play around with the sliders until you get a result that you are happy with.

Try it out for yourself here: https://tsargames.com/mini-mutant-hunter

https://store.steampowered.com/app/3045220/Mutant_Hunter/