Repl.it #webapp - "Stop wasting time setting up a development environment. Repl.it gives you an instant IDE to learn, build, collaborate, and host all in one place." Not sure this is related to email.
mailgun/transactional-email-templates - "Transactional HTML emails often get neglected. Styling HTML email is painful. Tables, inline CSS, unsupported CSS, desktop clients, web clients, mobile clients, various devices, various providers. ❡ We’ve tried to remove some of the pain for you and open-sourced a collection of common templates for transactional email."
phpList - "Powerful email marketing with specialist support and tailored pricing, powered by Open Source. That's why 75,000 organisations in 35 countries trust phpList." Seems like it's a transactional email service.