CSS ICON, not just a decent sized collection of icons made entirely with CSS but also a very slick animated function to swap between two icons.
CSSCO demonstrates how to use CSS to create some very nifty filters for images.
In The Future of Loading CSS, Jake Archibald takes a look at how best to load CSS. Up to now, as CSS normally blocks page rendering, we've usually combined all styles into one file and loaded them after the main content has been downloaded. However, an update to the Chrome browser, bringing it into line with Microsoft's Edge browser, could help to change CSS loading best practise. The general idea is that we load multiple smaller CSS files that in turn render the content that directly follows it, resulting in a more progessive page render.
Need some simple CSS loading elements? Try these
Flexbox-Framework, a simple grid system that uses the Flexbox CSS approach for layout.
Boy, a lightweight version of Boilerplate, with extra bits for older browsers.
If this list over at statusIE is anything to go by, then it's clear to see that web browsers are becoming extremely complex pieces of software. A few developments that sound intriguing are Box Alignment, CSS Calc, CSS Intrinsic Sizing, CSS Variables, Drag and Drop Directories, HTML Imports, <img srcset>, Masks, <picture> Element, Shapes, Web SQL Database, WebP image format support, and all the Canvas protocols. Lots to get excited about.