Dimensions Toolkit - Chrome Extension for designers to test responsive websites.
Jinja2 - Jinja2 is a template engine written in Python.
One Click Test - Tool for quickly testing your design layout in one click.
NANO – jQuery Template Engine - NANO is a simple and open-source jQuery Template Engine developed by trix.pl and released under the MIT License.
Flexbox Grid - Grid based on CSS3 flexbox
Pug - Pug is a robust, elegant, feature rich template engine for Node.js