- Fonts CSS
- Offers cross-browser typographical normalization and control.
- Reset CSS
- Offers cross-browser normalization of the default rendering of HTML elements.
- Grids CSS
- A suite of seven web page templates and the ability to nest grids of one to four columns within the content area of those templates.
With three very small files you have the ability to normalize rendering between browsers and set up a table-less layout within minutes.
I think that these libraries are useful in their own right, but the idea itself is even more important. The practice of programming thrives because of prebuilt libraries that allow developers to worry about the business at hand instead of the details of the platform. I think that CSS libraries can do the same thing, allowing developers to build bigger applications in less time.