Veeam Backup - Backup and restore VMware and Hyper-V virtual machines with Veeam Backup Free Edition. Unlimited hosts and VMs. Free forever.
imapsync - Console-based utility for migrating IMAP mailboxes.
Zerto - Virtual replication & recovery solution
Gmvault - Backup the emails in your Gmail account.
Acronis Backup and Recovery - Acronis Backup is a data recovery solution that offers more ways of storing and recovering drives, folders and files as compared to other similar solutions.
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.