One of the Influencers was interested in sharpening their HTML skills and was looking for some formal training on Responsive Coding for email. Here are some of the suggestion:
1. Only Influencers:
The OI Best Email Practice archives contains some of the best Email Style Guides and Resources for learning HTML Email Coding. You can find it here: Email Design Style Guides.
2. Frontend Masters: Responsive HTML Email Design
Taught by OI member and winner of the EEC's 2015 Thought Leader of the Year Award, Justine Jordan is one of the top masters in Email Design today. And be sure to check out the Email Design Conference sponsored by Litmus.
3. Unmasking HTML Emails
A course from Code School taught by Dan Denney. Explore the nuances of email clients and how to build designs for them with inline styles, tables for layout, and conditional comments.
4. General Assembly: Intro to Email Marketing
A regular series of email marketing classes taught leading email experts including OI Member Kristin Bond. Check the page for the next class time.
5. Professional Email Design
A 139 Page Course: Professional Email Design is a guide to understanding the components of HTML email design.
6. Lynda.com
Lynda.com contains many courses on creating Responsive HTML