MJML - The open source framework for responsive emails

MailPace - A Transactional Email Provider from the creators of idbloc.co - for apps, websites and anything else

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.

Swink - Short links with stats and automatically branded QR codes

Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.

Urlnet - Dead simple anonymous url shortener