@Mittineague Did you just play me with a classic engineering/developer joke? 
Sure, you don’t run out of colors in technical perspective. But it is can be difficult to develop scheme of colors that play well with the overall theming and each other. If you have five categories, it is super simple - just use https://coolors.co/ . But when you have 10-15-20 categories, it gets increasingly difficult. And the scheme should even be future proof, in case one wishes to add more categories…
@mark In addition to categories there are sub-categories. I have been tinking of a color scheme, that would “scale” vertically and horizontally. The root level categories would have different color, and the subcategories would be lighter shades of their root?
Root category sub-category
Red light red
Green light green
Blue light blueAnd if you have more than one sub-category, the idea would be to use different levels of white shading 25/50/75 would give you 3 sub-category colors. Haven’t tried this in real life though.
And yes the cultural color associations make it even more complex. Our local rival team goes with a green & yellow jersey, which limits the usage of these colors. The Finnish Elite League has black & white branding, so categories related to the League as a whole should prolly leverage that, and so forth.