color.koya.io alternatives

Color Hunt is a fantastic resource for designers, artists, and anyone interested in color theory and aesthetics. This platform offers a curated collection of color palettes that inspire creativity and streamline the design process

This tool has been created ages ago, but it just plain works. If you can have the image URL ending in .jpg, just add it to the tool, and there you go: 10 most used colors get extracted. Obviously, the UI is from another era, it can't process pics that as embedded in pages via complex plugins etc. But it doesn't matter.