Animation libraries are collections of pre-written code that help developers create animations in their applications or websites. These libraries provide ready-to-use functions and tools, making it easier to implement complex animations without starting from scratch. Popular examples include GSAP and Anime.js, which allow for smooth transitions and effects. Using animation libraries can enhance user experience by making interfaces more engaging and visually appealing. They often support various features like easing functions, timelines, and responsive design, enabling developers to create dynamic content that adapts to different devices. This saves time and effort while ensuring high-quality animations.