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.