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.
There are a couple of unofficial Android clients on F-Droid:
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.