I wrote a library for animating image backgrounds on the web using After Effects style filters and transitions:

https://aeroheim.github.io/midori/

It's basically a post-processing pipeline implemented with Three.js and WebGL using a few shaders that I wrote.

I created it primarily because I needed it for one of my current projects, so the use case is fairly niche and mostly only relevant for stuff like creative coding. It was my first dive into computer graphics however, and I learned a TON about computer graphics in general and had a lot of fun writing the library.