We have a responsive email framework used for marketing and maintained by an external agency (not in github).
This is a first pass at giving out some of the code for service teams to use.
So far there is just a basic service email template here that can be easily amended for use on your service.
More templates and the individual modules to build up varied designs will be migrated over time.
For more info give Matt Tyas (matt.tyas@coopdigital.co.uk) a shout on email or Slack.