I just came across this well-written link for our color theory reference library:
https://evilmartians.com/chronicles/oklch-in-css-why-quit-rgb-hsl
OKLCH is kinda like OKLAB but with polar chroma/hue coordinates instead of cartesian A/B coordinates (A = green/red, B = blue/yellow). it has some other advantages, explained in the article, and is now supported for CSS code on modern browsers. We may someday stop using RGB hex codes to define color altogether (as these guys are already doing).
Not sure how relevant this is for Nodebox right now, but it's something to keep an eye on.
ALSO, here is a link to an interesting color palette defined in OKLCH space: