Y'all have got to check out the color palette widget wizardry of David Aerne. Seriously, the guy's prolific. The first link is similar to OP's, an image color palette extractor:

https://okpalette.color.pizza

https://meodai.github.io/RYBitten

https://rybitten.space

This might be the best color palette generator I’ve ever seen. I used to work in Operating Systems, and trying to get a good color palette from a photo is HARD. A lot of very smart very well paid people have dedicated years of their life to this type of thing. Really fantastic work.

If the author of the blog post ever comes across this thread/ comment, bravo and I hope you feel pride in your work and I’d go so far to say discovery.

Related from same author: Generating a color spectrum for an image https://news.ycombinator.com/item?id=47783062

This is cool, I’m going to try write my own implementation to follow along as a learning exercise

Interesting design choices.

Have you ever tried allrgb.com? The idea is to use every 24-bit RGB triplet once and only once. Many people naturally choose 4096x4096 as the final image size.