It is too hard to build coherent and accessible themes with the right colors. This should help.

HSV(HSB)/HSL/RGB/Material color picker inspired by all the good design for your amazing flutter apps.

Dart port of HSLuv, a human-friendly alternative to HSL based on human experiments.

Color library for dart as a trustworthy port of kandinsky-js - Create dymanic and fixed gradients, convert from/to rgb, hue, hex, hsl and css colors.