MailStore - MailStore Home - A 100% free single-private-user desktop solution
MultCloud - Multiple Cloud Storage Manager: Migrate, move, sync, copy, backup and transfer cloud files with MultCloud, which supports Dropbox, Box, Google Drive, Mega, OneDrive and FTP, etc.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Cloud Combine - Cloud Combine is a browser and manager for the cloud services.
Gmvault - Backup the emails in your Gmail account.
Apigee - Intelligent and complete API platform