Came across this via the CSS3/HTML5 list on LinkedIn The page heading implies that they are all responsive but that's not the case. Haven't tried any of them as yet but they look worth investigating, for inspiration if nothing else.
http://www.designrazzi.com/2013/free-css3-html5-templates/
CSS Tricks have a large Snippets collection that can be an invaluable resource. It has snippets for HTML, CSS, htaccess, PHP JavaScript, jQuery and WordPress.
Even if you don't have a specific need it's well worth looking through for inspiration.
http://css-tricks.com/snippets/
jQuery Rain gives the latest list of their 'nominations' for the 100 best jQuery plug-ins.Some you'll recognise, some you won't, many you'll want to try. A couple that I'll be looking at seriously are FlowType.JS, which responsively adjusts font size and line height based on the width of the containing element, and slimMenu, which creates responsive menus on the fly (in a similar way as I did in one of my responsive menu demos) ......