If you have a rooted phone, an older android version, or the ability to access the android/data folder to move files around, I hear some pvz2 mods are pretty good. Only ones I can personally say are good are Refloureshed and Eclise, though it's been a long time since I've played Eclise. Both are harder versions of vanilla.

• Coffee Golf
• mineswifter.com
• Tomb of the Mask
• Downwell
• High Rise by smpl
• Vampire Survivor

Swordigo https://play.google.com/store/apps/details?id=com.touchfoo.swordigo

Alto - very calming and engaging game where you go down a mountain on your snowboard trying to catch llamas and do aerial tricks. Excellent vibes, no bothersome ads or micro transactions i think.

Night of the Full Moon is incredible.

Sky Force and Kittens Game are the only two mobile games I ever played and still have installed on every phone

Minesweeper on fdroid

If you like puzzles, horror and all things weird, definitely try some of the games by Rusty Lake.

The entire Cube Escape series is available for free (a sort of excape the room puzzle).

Reigns is quite fun

I've rather enjoyed 20 Minutes Till Dawn

Board game adaptations tend to be good. Everdell and bottom of the ninth for preference.

Monument Valley 1 and 2.

Haven't found anything that isn't microtransaction and ad-riddled trash or a port of an older game since.

Le Parker is my favorite side scrolling platformer on mobile that no one knows about.

There's an app I really like called Minireview, focused on finding and reviewing mobile games.

I Love Hue and I Love Hue Too. Also, My Friend Pedro. That one's pretty short though.

Atomas is pretty fun, it's super simple and looks really good

Slay the Spire. Join us.

You could get some minigame type games from fdroid. I have a tetris game and a 2048 game from fdroid. There's also Super Tux Kart if you want something 3D

Super auto pets is incredibly based

My favorite mobile games are

Don't starve

Dead Cells

Emulating old RPG games through Delta or Lemuroid

Kingdom Rush has been fun and not needy. (The first one?)

I Love Hue, both 1 and 2

I just want to kill some time

Pokemon sleep and take a nap

Dunno if anyone mentioned Badland yet.

Looks difficult to play but is so well designed that it isn't

Sky Wings is pretty fun. It's super arcadey, has different ships with different abilities and shooting styles, different modes and difficulties. I've put in quite a few hours over the years.

The Flow Free puzzle games are pretty fun imo. I have most of the different ones installed on my phone, and some years back I actually bought a bunch of the expansions for the base version so I have a ton of puzzles to go through.

Peglin is super fun. It's wood-described as a peggle rouglike

Fancade is also great. It's an open engine for little arcade games, so there's always something new to play. There's different modes like an adventure mode and a battle mode. There are IAP's but they're purely optional and very unnecessary.