Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.
Pistachio Email Templates - Delicious newsletter templates built for automation
Really Good Emails - A large collection of good product email design.
Gmail Email Templates by cloudHQ - Copy a successful company's email template in 1 Click
Good Email Copy - Email copy from great companies.
Transactional Email Templates by Postmark - Open source email templates for use in your SaaS app.