Visual Marketing Automation - An insanely fast automation builder by ConvertKit
Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.
Visual Funnels Maker from Customerly - Create powerful marketing behavioral funnels
MJML - The open source framework for responsive emails
HubSpot Free Email Marketing - Powerful drag and drop email marketing in the HubSpot CRM
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.