I use git-annex to:

• manage my research data, partly also with DataLad
• sync and backup personal documents
• sync media files to and from my SailfishOS phone
• sync, organise and backup a huge media collection
• experiment doing inventory management

I made a Thunar plugin for git-annex, here's a 📹 screencast.

At the Tübix 2023 I gave a (German) git annex workshop, of which you can find a recording of the initial talk 📹 here in the fediverse and 📹 here on Odysee.