imapsync - Console-based utility for migrating IMAP mailboxes.
Code42 - Code42 is a SaaS solution for enterprises that secures all user data on one secure platform, leaving you and your business secure in the knowledge that both your employee's and customer's data is protected. Read more about Code42.
Gmvault - Backup the emails in your Gmail account.
SolarWinds Backup - Modern server backup software
Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.
Druva inSync - Your device may be lost, but your data isn’t with Druva inSync™ Integrated backup, eDiscovery and compliance monitoring.