Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Classy - Expressive, flexible, and powerful stylesheets for native iOS apps
Groups.io - Email and web based discussion group software, includes archiving, emails, wiki, polls, file...
Agilon One - Agilon One is a Nonprofit CRM software solution that connects and gathers information on constituents.
Gaggle Mail - Gaggle Mail is a simple and easy to use email list manager.
Little Green Light - Illuminating Data. Advancing Nonprofits.