This is a Houdini SOP node that samples colors from an image or the screen.

Colors can be sampled by drawing on the image/screen or by using points on a line, a grid, randomly scattered points or with input points. It's also possible to sample the most frequently occurring (or dominant) colors.

The sampled colors are stored in a color ramp where they can be modified in various ways and can also be exported to an image or a JSON text file.

Download from techie.gumroad.com.

More info at techie.se.