Gammadyne Clyton - Clyton is an email client with advanced security and spam filtering features.
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
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
The Bat - The Bat! is a secure desktop email client for Windows, designed to protect your correspondence against third-parties and to save your time.
FairEmail - Open source, privacy friendly email app
MyEmail - MyEmail is an online service that works as a free email service system making its clients able to check their emails from any part of the world.