Obelisk.js
JavaScript Engine for Building Isometric Pixel Element with HTML5 Canvas
jQuery QR Code
qrcode generation standalone (doesn't depend on external services)
Html2canvas
Screenshots with JavaScript
Paper.js
The Swiss Army Knife of Vector Graphics Scripting – Scriptographer ported to JavaScript and the browser, using HTML5 Canvas. Created by @juerglehni & @jonathanpuckey
Processing.js
A port of the Processing visualization language to JavaScript.
Joint
JavaScript diagramming library
Isomer
Simple isometric graphics library for HTML5 canvas
Croppie
A Javascript Image Cropper
Svg.js
A lightweight library for manipulating and animating SVG
Raphael
JavaScript Vector Library
Bonsai
BonsaiJS is a graphics library and renderer
jQuery Focuspoint
jQuery plugin for 'responsive cropping'. Dynamically crop images to fill available space without cutting out the image's subject. Great for full-screen images.
Snap.svg
The JavaScript library for modern SVG graphics.
Clmtrackr
Javascript library for precise tracking of facial features via Constrained Local Models
Graphicsjs
A lightweight JavaScript graphics library with the intuitive API, based on SVG/VML technology.
Proton
A particle engine for html5
Image Mapster
jQuery plugin for enhancing HTML Image maps