DreamMail for Mac

As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements handled by Mozilla.

Microsoft Outlook is an email client with useful productivity features such as calendar and task management. It supports connecting to various types of email accounts, including Exchange, Gmail and Yahoo Mail.

Postbox is a nicely-designed utility created for people who use email services often. This application works with many IMAP or POP account types, such as Gmail, Yahoo!, Fastmail, iCloud, Outlook 365, and many others.

GyazMail is an e-mail client that is developed from scratch to be a simple, easy-to-use e-mail client with many features, based on the Cocoa framework. This software will be distributed as shareware (undecided on details at this point).

MailMate is an ambitious, powerful email client for OS X. It is designed for and only supports IMAP while still working in full when offline. MailMate has state-of-the-art searching capabilities and correspondingly advanced smart mailboxes.

Howard is a mail client that notifies you about incoming messages on your personal account. You will receive subtle visual and audio notification whenever someone sends you a message, and you will have the chance to check it on the spot.

Airmail 2 is a new mail client designed for Yosemite with fast performance and intuitive interaction. This version of Airmail brings an entire new engine, which allows for a much faster experience.