SaaS Email Templates - Responsive HTML email templates for SaaS startups
Transactional Email Templates by Postmark - Open source email templates for use in your SaaS app.
Pistachio Email Templates - Delicious newsletter templates built for automation
Email2Go.io - Perfect emails are born here
Email Template Generator - Email templates for your important relationships
Grab Digital - Unlimited branded, ready-to-send emails at $499 per month