FTPbox - FTPbox is an open-source application that allows you to synchronize your files to your own host...
GNOME Commander - GNOME Commander is a "two-pane" graphical file manager for the GNOME desktop environment.
Dropbox - Online Sync and File Sharing
xfdesktop - The xfdesktop application manages the desktop backdrop.
Syncany - Syncany is an open-source cloud storage and filesharing application.
CLEX - CLEX is a command-line interface-based file manager for managing and editing project files, no matter where they are stored.