Mail apps discussed lately; a few months ago where Newton shuts down apps on all platforms. This is as per the announcement. Spark with new features supports recently with the availability of iOS and macOS. With Airmail today, there is an update of Mac app with a slew of new features.
For the Mac app, Airmail supports officially macOS Mojave for the native Dark Mode. The accent colour layout improves support for Voiceover and OmniFocus 3.
With other Mail clients, Airmail is capable of mail syncing. This is with login information via iCloud, for easy to stay connected devices.
For Gmail users, a push email pulls to use a third-party app. This is where the stock iOS and macOS mail app does not support push email. This is back to fetch while falls. With Airmail for macOS on the Mac App Store is available for $9.99, is where the iOS variant available on the iOS App Store is for $4.99.