For those who are not familiar with Bruce MacEvoy’s Handprint website, this guy knows more about color theory than almost anyone who has ever lived. Not the world’s best organized site…. Start here: https://www.handprint.com/HP/WCL/water.html

I spent about six months working on adding new pigments to my palette, and his research was invaluable. Highly recommended for anyone who is intermediate at watercolour. For beginners, he has a page that recommends some beginner palettes, which is quite useful.

For those looking − as the GP said, it's not fantastically organized − pigments information is available here: https://www.handprint.com/HP/WCL/waterfs.html. Top links yield access to pigments, organized by "color family".

Two other similar resources on pigments − always good to check what's in the tube before buying!

https://www.kimcrick.com/pages/blue-art-supply-pigment-datab...

https://www.artiscreation.com/Color_index_names.html