Bulma is a free, open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.

MJML is a markup language designed to reduce the pain of coding a responsive email. Its semantic syntax makes it easy and straightforward and its rich standard components library speeds up your development time and lightens your email codebase.

HTML5 JavaScript Charts that are built on top of HTML5 Canvas Element. Renders across devices & is 10x faster than SVG based Charting Libraries.