Standard skills that come with a player don't need to all be marked, but the skills that you add should be easily recognized by your opponent
The letter 'B'. Fairly easy recognition.
The letter 'W'. Pretty easy, too.
The letter 'G'. We are good at this now.
This is mainly an alliteration thing for the above skills
Leave it to the elves to mess things up... but they are skare lil' chickens with Dodge, so Yellow.
Up for your own interpretation... but things that your opponent will want to be wary of like Tackle, Mighty Blow, Claw, Pass Block
At this point, it's up to you. Orange, purple, pink, black, sparkly, whatevs... as long as the other colors aren't doing things you'll be fine.