Three of my personal goto free options:

Nonograms are pretty simple logic puzzles in the same vein as Sudoku, but I enjoy them a lot. The app I personally use is Nonograms Katana.

Super Auto Pets is a really good, streamlined auto-battler. If you’ve ever played Autochess or Teamfight Tactics, its the same idea, but stripped to the down to the core principles and with a cute animal theme. Each turn you buy animals with abilities, then enter combat with another player and the animals automatically fight. Win 10 battles without running out of lives to win.

And not technically free without sailing the seas, but you should also be able to emulate gba games easily. Even if you don’t like playing more precise games with the touch controls (like me) there are a few great turn based games like Advance Wars and Fire Emblem.

I suggest downloading roblox, sure it has a lot of garbage games but it has some hidden gems

Simon tathams puzzle pack

Any of the “colors” series from ‘bart bonte’ (search yellow, or orange, or blue and he should be the first to pop up, his other games are good too)

Balatro (the only one I’m not sure how light weight it is, I think it should be pretty light weight)

(As others have said, lichess)

Pythagorea

Magic research 2

Rebuild 3

Any of the “pathpix” series

Slice and dice

Unciv

A hundred more recommendations that are “okay” level of fun

There’s an idle game called “smashing simulator idol” and in it, all you do is break pots and pans that fall from the sky by tapping/clicking on them. It’s simple and extremely addictive.

All in Hole.

It really is a stupid game, but sometimes you just need occupied for a few minutes.

You slide a hole around and things fall in it. The hole gets bigger, and bigger things fall in. It’s strangely satisfying.

These were listed yesterday

https://lemmy.world/post/23416167

Also, Andor’s Trail is a huge RPG. Plenty of grind.

• Kakuro
  • sudoku like puzzle game about adding up rows/columns
• Slice and dice
  • dice based rpg, may be a bit much on a slow phone, but timing doesn’t matter so it could work
• Melvor Idle
  • Runescape idle, basically an rpg idle game

2048, 10000000000

Seconding Simon Tatham’s Puzzle Collection. Quite a number of different puzzles, very lightweight.

80 Days is a neat game with a cool setting. Not free though.

Dungeons of Dreadrock was a nice puzzle game. I spent a good amount of time on that.

Suika Game The same great game for Switch, now available on mobile. Combine like fruit to evolve them into larger ones- keep going until you get watermelons. There are physics-based elements and if you overflow the play area, you lose.

OK, I’ll recommend you a few that are all open source, simple, free, with no ads, and should be handled by just any phone. You can find the games in f-droid between other places.

For those that are into crosswords: Forkyz

A slightly different take on sudoku style game: Gauguin

A game to place pieces removing full lines both vertically and horizontally, kinda like Tetris but pieces are not falling and you just put them wherever you want: 1010! Klooni

A tower defense game using hand drawn graphics: Anuto TD

And one I have from the play store, not open source, that is a clone of minesweeper, called… Well you can guess it: Minesweeper for android

All of those I have used on my own device and have worked great, definitely good time killers if you are into any of those kind of games.

https://f-droid.org/packages/dev.lonami.klooni/

I like Sudoku