Normalize.css
Normalize.css is a small CSS file that provides better cross-browser consistency in the default styling of HTML elements. It’s a modern, HTML5-ready, alternative to the traditional CSS reset.
Project site: http://necolas.github.com/normalize.css/
Underscores.me
Hi. I’m a starter theme called _s, or underscores, if you like. I’m a theme meant for hacking so don’t use me as a Parent Theme. Instead try turning me into the next, most awesome, WordPress theme out there. That’s what I’m here for.
Project site: https://underscores.me/