Mailo - Mailo is an email client where you can send and receive emails to and from anyone with an email address.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
HEY - Email at its best, new from Basecamp.
Roundcube - Web-based IMAP email client
Soverin - Soverin is the honest email service that doesn’t sell your data.
ProtonMail - Secure email with absolutely no compromises. Get your free encrypted email account today.