As of right now, we're only reviewing and publishing HTML and React themes. There are few reasons for this, but it's primarily that we only have the staff expertise in those two for now, though we're working on expanding that soon!
We will be creating a guide for React themes with some best practices, similar to how we've done for HTML templates, here in the Help Center.
For other languages, namely Angular and Vue, we are working on creating guidelines and hiring so that we can efficiently and effectively review and publish those as well. If you plan on creating a theme from one of these languages, please read about how exclusivity works with these theme variants.
We anticipate having guidelines and review processes in place for Vue and Angular during Q3 2019.