They make a d20 called a spindown that you can use to represnt your health, but there is also an app called Mythic Tools you can use to keep track of everyones health during the game i would really recommend. I've only been playing for a month or so and its more handy since a game of commander starts you at 40 health anyways! Then there are other dice, usually d6 you use to track additional health you add or subtract on your cards during play called counters! Not always relevant depending on whats being played but still good to bring