Really Good Emails - A large collection of good product email design.
Pistachio Email Templates - Delicious newsletter templates built for automation
Email Kick - Email designer and analytics for your transactional emails.
SaaS Email Templates - Responsive HTML email templates for SaaS startups
Stamplia - High converting and beautifully designed email templates
One Click Email Templates - Enter your URL for 14 branded email templates for free 💌