These dice were designed to be the Swiss Army Knife of ccg/tabletop dice. They can be used for Magic: The Gathering, Disney: Lorcana, Arkham Horror, Lord of the Rings LCG, Shadowverse Evolve, Marvel Champions and many other games. These dice are purposely generic to fit as many games as possible but with symbols that are very useful across many games.
+1 AND -1: These are the most straightforward, you can use these for any stats that go up or go down, be it a Power / Toughness stat in a CCG game, Wound Counters or Damage Counters for something like Disney: Lorcana or Attack / Life in Shadowverse Evolve.
ARROW: To me the curved arrow is something I’d use in a cramped space to indicate I had tapped a card in a TCG like Magic, or better yet as a Does Not Untap counter where you put this on a card that doesn’t untap and then you don’t forget and can take the counter off instead of untapping the card. These are also great for Lord of the Rings LCG Exhaustion Markers. You could also use these to indicate a direction on a game board or a card.
HOURGLASS: Can be used as an action spent indicator or as a timer. Put X hourglass counters on a card or event that is going to happen in X turns and then take a timer counter off at the beginning of each turn. Great time counters for Suspend in MTG.
EXCLAMATION POINT: Draw your attention to something with an exclamation point. Use it in Arkham on a location card, treachery, or player card so you don’t forget something important. I’ve been placing one on top of my MTG library so that I don’t forget to do something during my upkeep before I draw a card.
ⓧ FORBIDDEN: The X with a circle around it can be used to remind yourself not to do something or that you can’t do something, such as when a card effect in Arkham makes some other part of the game inaccessible.
These are just some examples that I can think of in just the games that I am familiar with. Let me know what you’re going to use your Universal Symbol Dice for!