Polymail - Native email app for email productivity.
Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
Airmail - Airmail is a lightweight and lightning fast mail client for Mac.
Mailscribe - AI-Powered Email Marketing
Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
Tonal - Machine learning digital gym + personal training built in