Spark 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.

Airmail 2.5 is a new mail client designed for OS X 10.10 Yosemite with fast performance and intuitive interaction. Support for iCloud, MS Exchange, Gmail, Google Apps, IMAP, POP3, Yahoo!, AOL, Outlook.com, Live.com.

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.

Mailsmith, the email client from the makers of BBEdit, is just as powerful and feature-rich as the text editor. It's a pity Mailsmith supports POP accounts only, and a — adequately empowering — rich-text editor could be a neat addition, too.

Hogwasher is a Usenet newsreader, which allows filtering articles, viewing threads as a tree, simultaneous downloading from an unlimited number of primary and backup servers as well as decoding binary files automatically...

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.

Kiwi for Gmail Lite can help you use various Google services right from your desktop. In this respect, it seamlessly integrates not only with Gmail but also the entire Google suite, which comprises Docs, Sheets and Slides.

SweetMail is an Internet email client that supports a multiple pane window, toolbar button setting, more contextual menu support more assistant features, address book, and IMAP4 support.

Mailplane is a Gmail desktop client designed for Mac users who wish to easily manage their Google mail account. This program comes as an alternative to using your default web browser for handling your Gmail account.

Opera Mail is a lightweight, customizable mail client. The application allows you to view multiple emails messages at once and navigate between them with ease.