GoodSync - GoodSync provides highly reliable file backup and synchronization for both individuals and businesses.
Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.
FreeFileSync - FreeFileSync is a free open source data backup software that helps you synchronize files and folders on Windows, Linux and macOS.
Google Drive - Access and sync your files anywhere
DirSync Pro - DirSync Pro: Powerfull synchronization and backup utility. It's portable, easy to use, open source, 100% free, 100% spyware-free, no limitations
Dropbox - Online Sync and File Sharing