Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Membee - Membee is web-based membership management software.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Galette - Galette is a membership management web application towards non profit organizations.
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.