Check out Simon Tatham's Puzzles for inspiration. Mostly logic and puzzle games, but they seem in line with what you're thinking.

Just remember quality over quantity.

classics like Snake, Puzzle Bobble, Angry Birds, etc. are worth emulating

*edit: emulating as in coding your own version not literal emulation

Ball on a maze controlled with gyro - simple acceleration and friction physics, just design levels with hazard pits, walls, pins, bumpers etc.

The helicopter game (though I guess now Flappy Bird would be the reference work) - http://arcade.flashgamearchive.com/game.php?game=Helicopter&m=0

Bejewled style match-3 puzzle game.

I've been thinking about attempting to make a foss Pokémon go like game, or walking focused virtual pet game, but without the dark patterns and monetization that constantly tries to separate you from your money

Absolutely enormous amount of work for character/monster design though, so for now I've just been thinking about it occasionally and will try to doodle creature designs as I think of ones I think might be interesting

At least gameplay doesn't need to be very complex

I was thinking just a regular android app to make it easy to use the stepcounting activity api or whatever though, rather than using godot, unless I think of functionality it really needs an engine for

Minesweeper!

Slime volleyball

Checkout merge maestro

Ok golf

Drug Wars!

Or y'know, a bowdlerized knockoff.