It’ll be very helpful to assign a background color to cards (single or multiple selected), so that they are visually distinct, and even act as group identifiers. A card’s connector lines can also follow the same color scheme.
that’s problematic because cards take on user colors when highlighted or edited while collaborating. So if you and I are in a space and my user color is ‘red’ then you’ll see red cards to indicate my current actitivity.
As a substitute, you can use long [[labels/tags]] inside cards, and give them any color you’d like