Great effort and reason to create this! I'm accustomed to using the Magic Wand tool in Paint.net[1] and Pinta[2] to select pixels based on color. Any chance you could add that functionality?
The name of this project brought many memories of the HP 48G to the forefront of my mind, after so many years. Its 1 bpp pixelated icons and drawings were indeed called GROBs - there are collections of these online. What a coincidental but fine name for a pixel-capable graphics editor.
Very actively developing this project, so hopefully it'll become a suitable replacement relatively soon. Please open GitHub issues or PRs if you have specific requests, happy to help.
[1] https://www.getpaint.net/doc/latest/MagicWand.html
[2] https://www.pinta-project.com/user-guide/wand/
I'm using Affinity v1 for some specific photo manipulation work, and the workflow is a bit convoluted.
Very tempting to make a specialized tool like this for that.
I'm glad to see entrants in this space!
It's really a shame the Paint.net author is so devoted to being Windows only.