Young-Helmholtz Theory of Color Perception

Color Theory 101: Color Wheels, Color Schemes, and Why Everything You Think You Know About Color Might Be Wrong

6 Color Harmonies You Must Know

Harmony’s colour palettes are useful for giving characters alternate appearances in night scenes, but also come in handy when animating characters for games: https://learn.toonboom.com/modules/animation-for-games/topic/animating-for-games?c=70