Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Mailman 3 - Dedicated Mailman 3 installation. Unlimited lists/configuration. Free subdomain at mailman3.com. Dedicated support for list admins.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.