I don’t know if this has been asked before, or is the appropriate thread for this, but what about an ability to edge/outline a token? It lets you add a bit more to distinguish between tokens of the same/similar colors, or could be used to represent an effect, similar to plastic coke bottle rings being placed on miniatures for things like poison and such.
You can always label them with their effect, I suppose, but that feels more cluttering or messy to me.
(I moved this out of the Feature Request: Tokens with Art thread because that thread is way to long and twisty. Seems like this is nicely self-contained as its own topic.)