Standard Notes is a big one for me. Thunderbird is the only way I access email on my PC. LibreOffice (or OnlyOffice) is regularly used on my end too. VLC is amazing and the only method I listen to music or watch videos on my devices. JabRef is a phenomenal bibliography tool I use for papers. Plus, Kdenlive is an amazing video + audio editing tool I use to clean up OBS recordings. Lastly, Syncthing is how I manage files across multiple devices. All of these are fantastic and a big aspect of my day to day.

Android:

• Bromite browser
• Aurora store (for Google Play Store apps)
• NewPipe (youtube)
• K-9 Mail (e-mail)

Linux:

• Mozilla Thunderbird (e-mail)
• LibreOffice (documents)

And others that have been mentioned

If I had to choose the top one, it would be self-hosted NextCloud, with a focus on its PhoneTrack plugin and corresponding Android app. Finally a FOSS privacy-friendly way to share my location with my family.

• 2FA: Aegis
• Podcasts: AntennaPod
• Passwords: Bitwarden
• Email: ProtonMail
• Browser: Firefox (and Fennec for Android)
• Search: DuckDuckGo
• Notes: Joplin
• YouTube: Piped (and LibreTube for Android)
• Maps: MagicEarth
• Streaming Music: ViMusic
• File Transfer: Snapdrop and Syncthing
• Messaging: Signal
• VPN: ProtonVPN
• Read It Later: Wallabag