Hello,
I made this graphic of default R21 COLOR Constants as a guide for me to find the right colors and wanted to share it with the community:
https://imgur.com/a/H11thSt
The spaces where there is no text means that the attribute is the same as c4d.COLOR_BG
and is blending in with the background.
Also, while making this, I found that the documentation lists one attribute that throws an error: c4d.COLOR_TIMELINE
AttributeError: 'module' object has no attribute 'COLOR_TIMELINE'