There are an awful lot of libraries that want to help you animate things on the web. These aren't really libraries that help you with the syntax or the technology of animations, but rather are grab-and-use as-is libraries. Want to apply a class like "animate-flip-up" and watch an element, uhhh, flip up? These are the kind of libraries to look at. I wholeheartedly think you should both 1) learn how to animate things in CSS by learning the syntax yourself and 2) customize animations to tailor the feel to your site. Still, poking around libraries like this helps foster ideas, gets you started with code examples, and might form a foundation for your own projects.

Vivus is a lightweight JavaScript class (with no dependencies) that allows you to animate SVGs, giving them the appearence of being drawn. There are a variety of different animations available, as well as the option to create a custom script to draw your SVG in whatever way you like.

"Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library."

Evolving animation.