SpamTitan - Comprehensive Email Protection. 99.99% Spam Detection. Blocks phishing, viruses, malware and other email threats.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
Sanebox - SaneBox is a cloud-based service that allows users to filter and manage their emails.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
MailCleaner - Cloud & on-premise anti spam software for businesses
Gmvault - Backup the emails in your Gmail account.