Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
tawk.to - tawk.to is a free live chat app that lets you monitor and chat with visitors on your website or from a free customizable page
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.