Very easy to use and quick to setup. I have used it personally.
Mailman 3 - Dedicated Mailman 3 installation. Unlimited lists/configuration. Free subdomain at mailman3.com. Dedicated support for list admins.
Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
Sympa - Sympa is an open source (GNU GPL) mailing list management (MLM) software.
Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.