Other than obvious physical traits:
Power of observation. Accurately seeing the game(s) and your opponents lets you anticipate, which is basically partially seeing the future and it of course is incredibly powerful.
Analytical mind: observing is the first part, then analysis to understand how or why you can take different approaches to win, attack, defend, etc. is part two. There are almost always another level of analysis to be done.
Curiosity: most people plateau physically long before they’re mental capacity in a sport is exhausted, but even at the pro level you still see many athletes that once they’ve made their paycheck or won x, they coast or stop developing. True multi-sport athletes are curious and diversely talented and this drive to understand helps them not just be satisfied with a single focus or sport.
I couldn’t believe it when I saw this yesterday. It’s so hard to draw a bead on exactly who he is between his senility, drug-addled body and pathological lying but it’s such a window into who he is; even though he’s taken over the playground and all his friends are running the school like animal house, he can’t even savor the enormity of the victory…he’s just glad he found his favorite pencil he thought someone took.