GoodSync - GoodSync provides highly reliable file backup and synchronization for both individuals and businesses.
Borg Backup - Deduplicating backup program with compression and authenticated encryption
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.
BURP - Burp is a network backup and restore program.
FreeFileSync - FreeFileSync is a free open source data backup software that helps you synchronize files and folders on Windows, Linux and macOS.
Restic - Easy: Doing backups should be a frictionless process, otherwise you are tempted to skip it.