<p>macOS Mail (OS X Mail) is a solid, feature-rich and spam-eliminating, but also an extremely nice and easy to use email client.</p><p>Spark is an impressive email program that, for instance, auto-organizes your inboxes and lets you postpone email easily as well as send quick one-click replies.</p><p>Pointing out key mail and letting you deal with the bulk in bulk; offering to snooze incoming emails and track the outgoing (with the option to block other tracking you); finding emails fast and saving searches for re-use, Canary Mail is one impressive IMAP email program. It makes email look good, too.</p><p>Aimed at the professional email user, Nylas Mail boasts mail merge, reminders, and the option to schedule mail—all available in a pro edition. For free, you get a clean and highly productive as well as expandable email program (that includes thrills such as link and open tracking, quick reply templates and undo send, for instance).</p><p>In addition to all you would expect from a smart, basic email program, Polymail lets you postpone email to be read later and in turn will track whether the emails you have sent were read… A pro version adds message templates and other features more.</p>Mozilla Thunderbird is a fully featured, secure and very functional email client. It lets you handle mail efficiently and with style, and Mozilla Thunderbird filters away junk mail too.The Opera email client is a slick and flexible interface that will satisfy almost all your email needs, and Opera integrates RSS feeds in this experience as well. Some may find the message editor lacking a bit in power, and the absence of support for encrypted email is unfortunate.Mulberry is a powerful and incredibly versatile email client available for all the popular platforms. If there is something Mulberry lacks, it is simplicity.<p>Mailsmith, the email client from the makers of BBEdit, is just as powerful and feature-rich as the text editor.<br/>It&#39;s a pity Mailsmith supports POP accounts only, and an—adequately empowering—rich-text editor could be a neat addition, too.</p>Alpine is powerful console email program that makes you use email productively with automation aplenty and nary a distraction.Never underestimate Mozilla! The email component of this open source browser is a solid performer, fully featured and handsomely usable.