Starability makes it simple to create accessible star ratings in a number of animated styles. And it's all done in pure HTML and CSS.
CSS Stats makes it easy to visualize information about your CSS, or CSS for various popular frameworks. It's easy to set up and requires node.
Give your designs that extra touch with this gorgeous collection of 800 Seamless Photoshop Patterns. A mix of color and grayscale, you'll get a huge variety of themes ...
Bootstrap Tour is an easy way to add a tooltip tour to your website. It even works if you don't use Bootstrap!
Multiple.js is an experiment for sharing backgrounds across multiple elements using CSS.
BlazeCSS is a modular CSS framework for building well-structured websites quickly. It's halfway between monolithic frameworks like Bootstrap and microframeworks like Milligram.
Hack.css is a dead simple CSS framework inspired by Markdown styling. It's super easy to install and use.
Ress is a modern CSS reset. It uses Normalize.css with some customizations to apply a solid base for your stylesheets.