Barcode generation library that works in both the browser and on Node.js http://lindell.me/JsBarcode
Jcrop (official) - Image Cropping Plugin for jQuery
qrcode generation standalone (doesn't depend on external services)
jQuery plugin for 'responsive cropping'. Dynamically crop images to fill available space without cutting out the image's subject. Great for full-screen images.
Simple isometric graphics library for HTML5 canvas
A canvas based drawing app that you can integrate easily on your website.
BonsaiJS is a graphics library and renderer
📐⚙ Library for creating 2D vector drawings for CNC and laser cutter machines.
A particle engine for html5