Comment by seanwilson

For this problem, I'm working on a tool to help create palettes where color pairs have simple and predictable WCAG/ACPA contrast by design (it has more features on desktop):

https://www.inclusivecolors.com/

So one approach is you create swatches of different colors that go from grade 100 (light) to grade 900 (dark), where the lightnesses are chosen such that all grade 700 colors contrast against grade 100 colors, all grade 800 colors contrast against grade 200 etc.

And then you know red-700 vs gray-100, green-800 vs yellow-200 and so on will contrast without having to check.

If you go to the Contrast menu, you can also explore how much stricter the APCA algorithm (meant to be more accurate) is compared to WCAG. For dark on light colors especially, APCA is much stricter about what contrast so you really shouldn't use WCAG for dark themes.

Also, if you go to the Examples menu and check out the Tailwind and IBM Carbon color palettes, you can see how the swatches in hand designed palettes vary their saturation and hue across grades in a non-linear way. So automatically picking if white/black contrasts the best is more straightforward (like the article mentions), but for more deliberate/branded palettes, you can't just generate a color with a simple lightness component shift, so this is more open ended.