Matter JS
a 2D rigid body physics engine for the web
Toastr
Simple javascript toast notifications
Mojs
motion graphics library for the web
Tfjs Core
WebGL-accelerated ML // linear algebra // automatic differentiation for JavaScript.
Konva
Konva.js is an HTML5 Canvas JavaScript framework that extends the 2d context by enabling canvas interactivity for desktop and mobile applications.
Parsley.js
Validate your forms, frontend, without writting a single line of javascript!
Particles.js
A lightweight JavaScript library for creating particles
Typeahead.js
A fast and fully-featured autocomplete library
Riotjs
The 1kb client side MV* library
Q
A tool for making and composing asynchronous promises in JavaScript
Fine Uploader
Multiple file upload plugin with progress-bar, drag-and-drop.
Editor
Next-gen, highly customizable content editor for the browser - based on React and Redux. WYSIWYG on steroids.
Gpu.js
GPU Accelerated JavaScript
Browser Sync
Keep multiple browsers & devices in sync when building websites. http://browsersync.io
Inferno
An extremely fast, React-like JavaScript library for building modern user interfaces
Onsen Ui
Custom Elements-Based HTML5 UI Framework for Building Your Mobile Front End
Zxcvbn
zxcvbn, named after a crappy password, is a JavaScript password strength estimation library. Use it to implement a custom strength bar on a signup form near you!