Workbox : JavaScript Libraries for adding offline support to web apps.
Tracery : A story-grammar generation library for javascript. Write grammar objects, get generative stories.
Anime.js : Anime.js is a fast, multipurpose and lightweight JavaScript animation library with a simple, yet powerful API.
It works with CSS properties, SVG, DOM ...
Photon : UI toolkit for building desktop apps with Electron.
Zepto.js : Zepto is a minimalist JavaScript library for modern browsers with a largely jQuery-compatible API. If you use jQuery, you already know how to use Zept...
A library to generate PDFs in client-side JavaScript.