I’m not sure how helpful this might be to the average user, but as somebody who’s brand-conscious and loves design, one feature I’d love to see would be an additional relation type for color.
Some quick mockups of how I imagine this could be accessed and seen on the user-end. Given how unlikely the average user might be to know hexcodes off the top of their head, I suspect a color-picker would be the easiest way for the user to select a color, which would then be displayed in hexcode:
I don’t know how complex a color-picker would be to integrate, but a system for dark mode or other themes would likely carry the background code to choose text color based on background color, so that much could be re-used.
Another possibility might be to just be able to add a block similar to a card and allow the user to choose a background color for it. Personally, I’d love the former option, since Anytype already gives me the opportunity to create databases with relations as columns, and being able to clearly associate specific colors with specific cells would be a secondary bonus for me.