I never imagined I'd like playing Tetris on the command line, on a terminal on my phone (termux), but here I am!
I couldn't find any Tetris app on fdroid, and just checked if pkgs had one. Lo and behold! It asked me to run pkgs install vitetris, and when I did, the tetris command was there to launch the game.
It's a two step process, as opposed to just launching an app, but it is very lightweight, no tracking, and FOSS.
For anyone with termux already installed and feeling a bit nostalgic, might be worth trying it out.
Sometimes an app needs to be updated to work properly with the latest operating system. I wouldn't say it's great to have no updates for a decade.
Well if you want an uptodate FOSS Tetris https://www.f-droid.org/packages/com.serwylo.retrowars/