A few I haven't seen mentioned:
- Moon+ Reader - My favorite ebook reader of all time.
- Tea Time - Simple timer widgets
- Simple Time Tracker - Track what you do
- NES.emu, Snes9x EX+, M64+ FZ - Emulators
- Thunder - Lemmy
- Root Explorer - file explorer
- Lichess - Chess, free of ads, no fees. Almost entirely FOSS.
Also +1 to the usual favorites: Firefox, Termux, Nova, etc.