Barracuda Email Security Gateway - Barracuda's Email Security Gateway is a powerful antivirus filter specifically designed to identify and eliminate email-borne threats, stopping hazards before they reach the network.

Mailwasher - Over 8 million people use MailWasher as their spam filter

Proofpoint Email Security and Protection - Learn about Proofpoint's email security solutions that protect organizations against threats such as email fraud, phishing, spam, bulk email, and viruses.

SPAMfighter - SPAMfighter and Microsoft have built the strongest and most effective anti spam filter for Outlook, Windows Live Mail, Outlook Express & Thunderbird

Cisco Email Security - Cisco Email Security protects against ransomware, business email compromise, spoofing, and phishing.

Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.