It would be nice to at least have the 7 colors of the rainbow available to us.
They are also used in science, in the electromagnetic spectrum, they are used in the Chromatic scale used for notation in music.
You actually already have 6 of the rainbow colors. You are missing INDIGO (dark blue).
Here is a Wikipedia article showing the seven rainbow colors: https://en.wikipedia.org/wiki/Rainbow#Number_of_colours_in_spectrum_or_rainbow
We thought of using the common rainbow scheme when first adding color labels, but from our testing Indigo doesn’t stand out enough from blue and purple so we just didn’t add it in the end.
Is this causing some sort of issue?
Well, it’s just that I’m actually writing a paper on the seven foundations of everything. We can find a pattern throughout all that exists which follows this principle of 7 characteristic including 7 musical notes, 7 chakras in the human body etc. And I’d love to be able to color code using the correct colors found in the rainbow. 
Ah… I see. Maybe pretend no color is Indigo for now? 
For sure I would love to have more colors. For colors not standing out enough, why not at least introduce 6 more color choices with the font inverted (in light scheme, anyway)?
My use case is that I’d like actual red for urgent/important things, not the washed out one we have now. Actual red with white font would be perfect.
There is too much other text in the list without any color…i’m not able to distinguish the text that should be in Indigo color.
Right, we’ll think about it some more when we have more time. Right now there are lots of higher priority stuff going on, hope that’s understandable.