Creating email templates can be a tedious task, with so many rules between different email readers, most of CSS not really working and us devs now so used to SASS and LESS, just the idea that they still use tables terrifies me a bit.
There’s the possibility of buying a template, but in my experience that may not be the best approach; companies that sell templates as a business model tend to obfuscate as much as possible of their product, and being HTML+CSS this means they will run some algorithm on it creating weird stylesheet keys and stuff just to make your editing life a painful hell.
So the alternative, apart from creating a very simple and plain email, is to go opensource. Yes. There are some opensource email templates out there, personally I found this one quite clean and useful.