Add color names packaged with ProPlot or saved to the ~/.proplot/colors folder. ProPlot loads the crowd-sourced XKCD color name database, Crayola crayon color database, and any user input files, then filters them to be “perceptually distinct” in the HCL colorspace. Files must just have one line per color in the format name : hex. Whitespace is ignored.

This is called on import. Use show_colors to generate a table of the resulting colors.