rsync, FastCopy, FreeFileSync, Robocopy, SyncBack, SyncToy, DirSync Pro, IPFS, Unison File Synchronizer, Iperius Backup, Syncovery, Bvckup 2, Yadis! Backup, Bareos, AutoVer, SparkleShare, Parachute, DropCopy, MultiCloudBackup, Lazy Mirror, snaprd, Xopero Cloud Personal, Blucoubackup, Time Drive, Back it up!, QRecall, RecImg, AISBackup, CascadePoint, Ferro Backup System, Attic Backup, Backup Scheduler: Time Editor, Horodruin, IdleBackup are some alternatives to Backer.