MailStore - MailStore Home - A 100% free single-private-user desktop solution
Rubrik - Rubrik delivers instant application availability for recovery, search, cloud, and development.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
CommVault - Commvault is a site search platform that helps legal or compliance officers and corresponding end users to explore and retrieve files and email across different applications, storage devices and computers.
Gmvault - Backup the emails in your Gmail account.
NAKIVO Backup & Replication - NAKIVO Backup & Replication offers a complete data protection feature set, including local and offsite VM backup and replication, support for live applications & databases.