Foss Apps that everyone should know

One of the things I struggle is to discover new or popular apps, because of the lack of stats on f-droid (privacy first, I'm not complaining). So I'm interested on the community knowledge.

For me the best ones are:

• Syncthing (device synchronization over LAN or internet without a centralized server)
• Omnivore (read it later and newsletter reader)
• Wifi Analyzer
• LocalSend (Multiplatform alternative to AirDrop)
• Proton: ProtonMail, ProtonCalendar, ProtonDrive, ProtonVPN (secure services with E2EE and full remote serve encryption of your data)
• DuckDuckGo: DDG browser, DDG Email protection, DDG app tracking protection
• Material Files
• Simple Galery Pro
• OnlyOffice (FOSS office suite)
• K-9 Mail (multi-account centralized email app)
• P!n (small notes/reminders on your notification bar)
• Termux A linux terminal for your android. Personally I use it for managing Git repositories on wich I store my personal notes
• Bitwarden Password Manager with free synchronization. Multiplatform also.