GoodSync - GoodSync provides highly reliable file backup and synchronization for both individuals and businesses.
SpiderOak - SpiderOak makes it possible for you to privately store, sync, share & access your data from everywhere.
FreeFileSync - FreeFileSync is a free open source data backup software that helps you synchronize files and folders on Windows, Linux and macOS.
Duplicati - Free backup software to store backups online with strong encryption. Works with FTP, SSH, WebDAV, OneDrive, Amazon S3, Google Drive and many others.
DirSync Pro - DirSync Pro: Powerfull synchronization and backup utility. It's portable, easy to use, open source, 100% free, 100% spyware-free, no limitations
CrashPlan - CrashPlan for Small Business backup software offers the best way to back up and store business & enterprise data securely - offsite, onsite & online in the Cloud.