Mobile games usually get a bad rep as they’re usually asset flips and/or MTX-ridden and/or ad-filled, etc., and I’m sure this is actually the case for most games on the app/play store. But are there any ones that are actually good, maybe just something to pass the time with?
Atomas was mentioned in another comment; I can vouch for it as well.
A Dark Room is a fun (if not somewhat short) text-based game.
Bonza and Smash Hit are good for passing the time.
Vector Classic and Shadow Fight 2 (Special Edition) used to be my favorites as a teen, though I otherwise wouldn’t recommend Nekki games since they’re full of ads and dark patterns.