eM Client
Email clients
Mailbird for Mac – The All-in-One, Lightning-Fast Email Client | Free Download
Polymail
Mailbutler
Inbox Zero
Mimestream
Airmail
Canary Mail | Best Email App for Apple iPhone, iPad & Mac
Email for Mobile | Edison Mail | Edison Software
The Power Email App - Postbox
BlueMail - The Best Email App for Windows, Mac, Linux, Android and iOS