This brought parchive/par2 to mind; as I recall, given an index file, which you could keep separate, you could do a rolling scan for the recovery blocks and fil

This brought parchive/par2 to mind; as I recall, given an index file, which you could keep separate, you could do a rolling scan for the recovery blocks and file blocks on the disk, even without the file system structure. Unfortunately, it sorta looks like that software hasn't been worked on in a while.