There are a number of libraries out there that wish to assist you with animating things on the web. These aren't actually libraries that aid you with animation syntax or technology; rather, they're grab-and-go libraries. Do you want to add a class like "animate-flip-up" to an element and watch it, uh, flip up? These are the types of libraries you keep an eye out for.
A Sass library for creating flexible CSS transitions and animations.
One of the big original classic CSS animation libraries from Dan Eden.
Tachyons itself is an atomic CSS library with a ton of utility classes for essentially designing anything by adding classes to what you need. tachyons-animate extends those by adding “Single purpose classes to help you orchestrate CSS animations.”
Vivify is sort of like Animate.css in the sense that it contains a lot of the same types of animations
You pick an animation you like and it gives you a class name you can use that calls a keyframe animation (you copy and paste both). The point is you just take what you need.
These animations, like rotations and pulses, that are specifically designed to run and repeat forevers.