I currently work on a system that gives every player their own deck of cards. The idea being that rhe player draw instead of roll. Every player gets their own favourite cards and abilities that trigger on specific cards or card types. For example every Ace is a critical success, every club (if that’s your color) deals double it’s value.
It could be cool to use poker hands as a replacement for dice rolls in a fantasy rpg. Like instead of rolling to attack, you “attack” by having a hand which is better than three 2’s. Like the “hand to beat” acts as a difficulty class. And then you could have certain game mechanics that key off of the suits or ranks in your hand, like you crit if your poker hand includes an ace or something like that.
Edit: another option, as my card game of choice is actually Cribbage, could be to use Cribbage hand scores as a sort of roll. They already use numerical points which are distributed around 0-20 (higher for really good hands). Then you could key mechanics off of number of 15’s, whether or not someone gets the Jack of the suit, etc.