Open source idle game, but not quite. It eventually expands beyond watching numbers go up, into a sort of roguelike, where you can wander the world and collect stuff. And die. Die a lot.
A Dark Room was where I first saw the @ symbol used to represent the player character.
Gridland
Also by double speak games, and open source gridland is a variant on the match 3 style. During the day phase, you accrue and store resources, and build stuff. During the night phase, you fight.