ProtonMail - Secure email with absolutely no compromises. Get your free encrypted email account today.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
KLS Mail Backup - KLS Mail Backup is an easy to use backup program that allows you to back up and restore your...
Mailvelope - Mailvelope open source project. OpenPGP in your browser.
Mail Backup X - Your one stop mail backup and archiving tool for Mac.