I try to run my phone on Free Software as much as I can.
I recently switched to LineageOS. I took it as an opportunity to do a full factory wipe and reinstall, to simulate a disaster recovery.
Here's a summary of the basic software I use:
- Operating system: LineageOS
- Application store: F-Droid
- Contacts and calendar sync: DAVdroid and Radicale. I posted some setup instructions some years ago, though it shuold be simpler now thanks to Let's Encrypt
- SMS sync: SMS Backup +
- File sync: Syncthing
- E-Mail: K-9 Mail
- XMPP/Jabber: Conversations
- Sat nav: OsmAnd
- Public transport information: Transportr
- Telegram: the Free client from F-Droid
- Hi-Fi remote control: M.A.L.P.
- Note taking: Lesser Pad