MJML - The open source framework for responsive emails

Campaign Genius - Send dynamic email content through any platform, instantly.

Stripo - Stripo is an all-in-one email design platform. We enable our clients to build emails of any complexity, including interactive AMP emails, really fast and easy.

GMass - GMass allows you to easily schedule emails, send out mass emails and mail merge campaigns and more with Gmail! Click here to learn about more features!

Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.

MailChimp Snap - Send simple, photo-based email campaigns from your phone.