How about a color that is a reference like 1 or 2 or 3 instead of a (0.2, 0.6, 0.5) vector directly. And this reference number would instead refer to the vector on a menu.
You could have as much reference colors as you want so to speak or like 10 or something per project or something.
Imagine your painting with reference 2, all that paint will act as reference 2=(vector color 2) until you changed the vector color 2 color into another one changing everything in the painting with that color.
This means you can have 2 reference colors with the same color and still act apart.
Case usages. Especially in animation. Ensures that the color is always the same as long as you use the reference color and if you change it it will affect the entire project on a frames ensuring stability of the color selected. This means even if it does not mix or blend it would still be usable with a very define use case.
If it is possible to re render the mix and blend to other color it would allow to help with character design and test variant colors on certain sections making variations easier without distorting colors with a filter using a bad color space.
So it maybe be called that color with a given shortcut or something like press ctrl+2 to select reference color 2 or something.
This would be similar to how vectors change colors in an entire group at one but in this case it would be in pixels.