Transactional Email Templates by Postmark - Open source email templates for use in your SaaS app.
HTMLEmail.io - Responsive HTML email templates for startups & developers
SaaS Email Templates - Responsive HTML email templates for SaaS startups
Startup Emails - Responsive HTML email templates for startups
Email2Go.io - Perfect emails are born here
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.