imapsync - Console-based utility for migrating IMAP mailboxes.
Hornetsecurity Email Archiving - Hornetsecurity Email Archiving is one of the advanced software that offers long-term, unchangeable, and secure storage of important company information, data, and flies.
Gmvault - Backup the emails in your Gmail account.
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.
Intradyn Email Archiver - Orca Email Archiver provides email archiving solution for local government and business.
Mail Backup X - Your one stop mail backup and archiving tool for Mac.