Don't know what features you have and haven't thought of implementing already but heres my 2 cents :>
- Card sorting, please.
- Instead of rocks filling up your remaining hand the player could have a single seperate rock card that keeps getting replenished, since there isn't really any difference between the rocks. (this isn't really a necessity and might make the hend feel too empty but worth giving it a try imo)
- Recipie book for potions you've already drank and now know the effect of.
Good luck with the game!