Mailman 3 - Dedicated Mailman 3 installation. Unlimited lists/configuration. Free subdomain at mailman3.com. Dedicated support for list admins.
Padlet - Visual boards for organizing anything.
Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Eduflow - Digital learning that actually teaches students something
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Flowlingo - Get fluent in a language through content immersion