What local apps do you sync via Dropbox/Syncthing or similar?

Hi HN! I want to start using Syncthing across my devices (Linux/Android), as I don't have a 24/7 server, and I'm aware of several apps or services not built to be multi-device that can be synced that way with success: KeePassXC, LogSeq, Obsidian, etc

I just learned about DecSync CC to sync contacts, calendars and tasks without a server and I was wondering... what other local apps do you sync via Dropbox/Syncthing or similar? How to make the best use of Syncthing in 2024?

DecSync CC: https://github.com/39aldo39/DecSyncCC and https://f-droid.org/en/packages/org.decsync.cc/