MirrorBackup.net - Mirror Backup protects from data loss by continuously monitoring files and folders, and backing them up to the cloud or a local drive when they change.
FreeFileSync - FreeFileSync is a free open source data backup software that helps you synchronize files and folders on Windows, Linux and macOS.
AnyBackup - AnyBackup is designed to keep two pools of volumes in sync with one another.
SyncBack - Backup software for the PC: powerful, easy to use solution for backing up and synchronising files on a local/network drive, the cloud, FTP server and more.
@MAX SyncUp - An advanced tool for Windows to compare and synchronize files and secure data backup either locally or to FTP/SFTP, Google Drive, and more.
GoodSync - GoodSync provides highly reliable file backup and synchronization for both individuals and businesses.