MiXplorer: Tabbed file explorer with many features. You can get it for free from their website, but it’s available paid on Google Play.
Symfonium: Music player compatible with many backends, such as local storage, WebDAV, Subsonic (which includes Ampache, Navidrome)
aCalendar+: Calendar app with many widgets. Best part is the persistent notification, which shows what’s happening today, and will happen tomorrow.
Cryptomator: Cross-platform file encryption program, also open source.
For some reason, Starcraft. There’s barely anyone who’s into it in my age group. Not that I got good, I just had so much fun in custom maps.