I've wasted too many hours on Shatter Pixel Dungeon.
You can get the source for OG Pixel Dungeon off GitHub, but there's a maintened version on the F-Droid store (Shatter Pixel Dungeon). There's some other free versions floating around too, not sure if they're on the F-Droid store too, but I know they're on the play store.
I can't say I've tried a ton but in searching for the same thing, I found Mindustry. It scratched this weird StarCraft-esque tower defense game that I didn't know needed scratched.
From what I can see Blockinger had its last commit 11 years ago. While it's not on F-Droid (still FOSS though), my Tetris clone of choice is Falling Lightblocks. One super cool feature is 2 player competitive on one device using 2 game controllers.