Thunderbird is a open source mail client developed and maintained by Mozilla foundation.

eM Client is a Windows based e-mail client for sending and receiving e-mails, managing calendars, contacts, and tasks.

Windows Live Mail is the successor to Windows Mail on Windows Vista, which was the successor to Outlook Express on Windows XP.

Kopano is an open-source groupware application suite originally based on Zarafa.

Microsoft Outlook is a personal information manager from Microsoft.

Postbox is powerful, intuitive, ultra-customizable, speedy task manager.

The Bat! is an email program for Windows that protects the correspondence and empowers the users to handle large amounts of emails quickly and efficiently.