Ask HN: A formula or library to generate color palettes?

Use case: I'm building a feature that allows a User to ask for e.g. a "sky blue" design. From there I would have "sky blue" as the dominant color, but I need a library or "best practice formula" to generate hex codes for text, headers, bullet point icons, accent colors, etc.

I want to be able to generate a complete CSS color palette from just this one fuzzy ask. A palette is maybe 8+ colors and asking Users to pick each is just asking for trouble. (Even better if I can generate 3 palettes and let the user pick one).

Is there a great resource for this?