imapsync - Console-based utility for migrating IMAP mailboxes.
SpamTitan - Comprehensive Email Protection. 99.99% Spam Detection. Blocks phishing, viruses, malware and other email threats.
Gmvault - Backup the emails in your Gmail account.
Sanebox - SaneBox is a cloud-based service that allows users to filter and manage their emails.
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.
ZeroSpam - Cloud email security & anti-spam solution