Dropbox - Online Sync and File Sharing
CKFinder - CKFinder is a powerful and easy to use Ajax file manager for web browsers.
ownCloud - ownCloud is an open source project enabling businesses to host their own cloud storage while maintaining regulatory and compliance needs.
Flmngr - Free PHP File Manager
Google Drive - Access and sync your files anywhere
Responsive Filemanager - RESPONSIVE FileManager is a free open-source filemanager image manager stand-alone and plugin for TinyMCE 4, CKEditor and CLEditor. It's possible to select files, images and videos from a server folder and upload them from your computer