I'm making some UI mock-ups for a tournament system. The scenario is that two players are being matched and then compete against each other. Colors is not an option because the system is going to implement in an existing system that already uses colors, and these colors may not always be the same.
The first idea I have is to use symbols.
EDIT: Note that the game/table it self is physical. Only the matching of players and the seating arrangement is done in software.