Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Gmane - Gmane (pronounced like "mane") allows users to access and participate in e-mail-based...
Mailing Group - Listserv - Allows you to run a free Listserv or email group right from your WordPress dashboard.
MailerLite - Affordable Email Marketing Software. Get all features (Segmentation, Automation, A/B testing) for up to 1,000 subscribers & send unlimited emails for free!
Mailman 3 - Dedicated Mailman 3 installation. Unlimited lists/configuration. Free subdomain at mailman3.com. Dedicated support for list admins.
Dada Mail - Email Marketing List Manager