Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
mailcow - An open source mailserver suite.
Gmail - Gmail is available across all your devices Android, iOS, and desktop devices. Sort, collaborate or call a friend without leaving your inbox.
hMail Server - hMailServer is a free e-mail server for Microsoft Windows.
Zoho Mail - Zoho Mail is a secure, encrypted, and enterprise-ready email solution, a suite of apps tailor-made for your organization's needs.
SmarterMail - SmarterMail is a next generation email management server that is offering several business collaboration and communication features as well.