Duplicati - Free backup software to store backups online with strong encryption. Works with FTP, SSH, WebDAV, OneDrive, Amazon S3, Google Drive and many others.
csync - csync is a lightweight utility to synchronize files between two directories on a system or between...
Restic - Easy: Doing backups should be a frictionless process, otherwise you are tempted to skip it.
Synchromat - Synchromat is file and folder synchronization software for Windows.
rsync - rsync is a file transfer program for Unix systems. rsync uses the "rsync algorithm" which provides a very fast method for bringing remote files into sync.
CopyQueue - CopyQueue - Copying under control.