imapsync - Console-based utility for migrating IMAP mailboxes.
MailCleaner - Cloud & on-premise anti spam software for businesses
audriga Email and Groupware migration - Easily migrate your email, contacts, calendar items and tasks to your new provider or server. No software installation is required.
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.