snap-sync is a command-line script that uses snapper snapshots to do incremental backups of btrfs subvolumes. The target use-case is backing up on removable media such as USB hard drives, though it also supports backing up over the network.

It is somewhat similar to btrbk, but snap-sync works interactively by displaying a list of mounted btrfs devices and then querying the user for each snapper configuration, whereas btrbk is configuration-based and does not care about snapper. Snap-sync does also have command-line parameters to perform backups without interaction.

I have packaged it on COPR (spec file) but I think it's useful enough that it could be considered for inclusion in the main repositories. It should be noted that it has some optional dependencies: pv for displaying progress during backups and notify-send for desktop notifications when the backup is done.