Really Good Emails - A large collection of good product email design.
GMass - GMass allows you to easily schedule emails, send out mass emails and mail merge campaigns and more with Gmail! Click here to learn about more features!
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.
Google Sheets Email Marketing - Email automation and validations directly from Google Sheets
Email Design System for Sketch - Sketch file with 10 email templates for designers
Elevatr Email Marketing Automation - Fast and easy email marketing software