Restic @resticThe restic backup program is such an unreasonably good piece of open source software... https://restic.readthedocs.io/en/stable/

It works reliably, quickly, the documentation is stellar and you can feel that CLI was carefully designed to address the needs of every user. It's low-level enough that you can integrate Restic with other tools or scripts, but it remains understandable for people without a PhD in filesystems.

It's one of those few tools that I know I can come back to at any time and it will still work.