Syncthing
Keeps folders in sync directly between your own devices.
Instead of Google Drive, OneDrive sync
Screenshot from syncthing.net, taken 2026-10-23. The images belong to their makers and are shown to help you recognise the tool. Ask us to remove one.
Syncthing copies changes between your own computers with no cloud in the middle, which makes it the purest answer on this list to rented storage. On the desktop it is excellent and has been for years.
It scores low on Self-direction because setup asks you to understand device IDs and folder sharing, which is more than most people want. On phones, the official Android app was discontinued at the end of 2024, and the recommended community fork went through a messy change of maintainer, so Longevity takes a hit too.