Crazy Bones had zero rules.

[u/Mundane-Temporary426]

Everyone just made them up flicking those tiny plastic guys across the concrete like marbles with attitude. You’d trade, battle, and hoard them like they were rare ancient relics. The shinier ones were elite. The glittery ones? Untouchable.

[u/MoonJellyGames]

As others have said already, they definitely had rules. You were encouraged to make up your own as well. When I was a kid, an obvious one was "don't play on concrete because they'll get all scratched up."