Finding gems in the world of FOSS can be a difficult task if you don’t know what you’re looking for. However, I can easily say that my top three are Antimine, Shattered Pixel Dungeon, and Minetest.
Antimine is your typical minesweeper game but it’s really well-produced and customizable. I hadn’t really played minesweeper much before Antimine, but I find myself picking up Antimine pretty often.
Shattered Pixel Dungeon is an awesome roguelike that proves rather challenging. The more you play it the better you become, and sometimes you’ll get some really great RNG and it just feels awesome.
Minetest on it’s own isn’t much of a game as much as it is a 3D block-game creation engine. It’s more or less the bones that make up a FOSS Minecraft, and with projects such as Voxelibre, it is a really fantastic Minecraft alternative!
What games do y’all play from F-Droid? Feel free to mention things that come from other repos than the ones that come with F-Droid out of the box!
I don’t play it that much, but Mindustry is probably worth looking at, a factory-building game in the Factorio mold.
https://mindustrygame.github.io/
Unciv is a reimplementation of Civilization V (with simpler graphics).
https://github.com/yairm210/Unciv
Not in F-Droid, but open-source: I very much like Cataclysm: Dark Days Ahead as a game, but it’s really better-suited to a PC, which is the platform it was originally designed for. It’s compute-heavy, and while the Android adaptation is usable on a touchscreen, it benefits from having a Bluetooth keyboard or something. Open-world roguelike. You can just download the apks directly. This has a steep learning curve; think Dwarf Fortress. Lots of depth, though!
https://cataclysmdda.org/
I’m not actually all that rabid about the touchscreen UI. Probably better solitaire UIs out there, but PysolFC is a fork of Pysol, a long-running Linux solitaire implementation. It has a ton of different games; my favorite is Eight-Off, a game that’s somewhat similar to Freecell, but less-widely played. I think that solitaire games are a good match for a phone platform, so worth having it or another solitaire game around.
https://pysolfc.sourceforge.io/
My own favorite is one that you mentioned, Shattered Pixel Dungeon, which I think is a good adaptation of roguelike gameplay to the touchscreen. Its creator posts on a Threadiverse community here, !pixeldungeon@lemmy.world.
This isn’t a specific game, but Twine-based games will generally work reasonably well on an Android web browser. These tend to be sort of multiple-choice choose your own adventure games, but span a wide range of genres. I don’t know of a single database cataloguing all of them, but there are a fair number out there on the Web.
For an example (not one I’d specifically recommend, haven’t even played through it, just hit Kagi for an example game that people were recommending):
https://pseudavid.itch.io/the-master-of-the-land
I really enjoyed Mindustry, even though I’ve never tried another factory-type game. The polish and depth was 100% there although I got lost at one point and didn’t know how to progress. That game really changed my perspective on what is possible for FOSS. Godspeed, devs
I lost an entire day to Unciv recently.