animate.css is a bunch of cool, fun, and cross-browser animations for you to use in your projects. Great for emphasis, home pages, sliders, and general just-add-water-awesomeness.
Dan Eden put together a stylesheet with some fancy CSS animations which are really easy to use. Simply add the classes animated and the animation name to an element and you are good to go.
I wouldn’t include the whole file just for one animation, but it is a good library for picking the animations you like and including them in your own stylesheet or vars.less.