5 Most Popular HTML5 Responsive Frameworks
Boilerplate is not a framework, nor does it prescribe any philosophy of development, it's just got some tricks to get your project off the ground quickly and right-footed.
Although it is not a framework I decided to mention it first because it is good starting
point for any HTML5 project.
It contains features that others don’t have e.g. cross-browser normalization,
performance optimizations, even optional features like cross-domain XHR and Flash.
Twitter Bootstrap is a free
Bootstrap is made with LESS at its core.
Foundation is the most advanced responsive front-end framework in the world. With Foundation you can quickly prototype and build sites or apps that work on any kind of device, with tons of included layout constructs (like a full responsive grid), elements and best practices.
It’s a bit ambitious, isn’t it? I can only add it’s built with Sass.
Skeleton is a small collection of CSS files that can help you rapidly develop sites that look beautiful at any size, be it a 17" laptop screen or an iPhone.
I met some commercial templates that are built on Skeleton.