MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
Constant Contact - Constant Contact offers email marketing, social media marketing, online survey, event marketing, digital storefronts, and local deals tools.
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
Campaign Monitor - Email marketing software built for designers and their clients to run successful email campaigns.
Mailjet - All-in-one email service provider that provides maximum insight and deliverability results for both marketing and transactional emails.