Thanks for giving something back and not just in this topic. 
I donât have any suggestions regarding specific Category colors for you particularly because of your need to avoid team color associations and I donât have the same cultural color associations as your users.
I just want to point out that it is worthwhile to integrate Category color theming with the Site color theming because they always interact.
For example, even if you want to have Category colors âsomewhat aligned with the overall brand and stylingâ, you donât usually want Category colors to repeat the site colors. The appearance of vitality in a site declines when the colors appear too uniform because they are repeated, as your Category colors do - but the blue and orange are a good combination. The same with a lack of contrast between colors. We donât want them too lively (as discussed in The end of Clown Vomit, or, simplified category styles ) but we also donât want to hinder engagement by making them appear too bland (e.g.if color seeding isnât handled well Create a complete color scheme based on one seed color feature).
So it would be good to have more Site and Category color automation which would reduce the need for many of the site customizations that appear in this forum. Maybe itâs time to look at extending What about an easier styling/theming system? / Programmatically adjusting color variables with SASS to Category colors?