For those who don't want to use the bird site, here are all the links from the main thread:
https://orama-interactive.itch.io/pixelorama
https://rodzilla.itch.io/material-maker
https://deakcor.itch.io/pixelover
https://tools.kenney.nl/kenshape
https://assetforge.io
https://azagaya.itch.io/laigter
https://wonderdraft.net
https://dungeondraft.net
https://store.steampowered.com/app/948220/ColorTool