Lightgallery.js
Full featured javascript lightbox gallery. No dependencies.
Paper.js
The Swiss Army Knife of Vector Graphics Scripting – Scriptographer ported to JavaScript and the browser, using HTML5 Canvas. Created by @juerglehni & @jonathanpuckey
Vegas
Vegas is a jQuery plugin to add beautiful fullscreen backgrounds to your webpages. It even allows Slideshows.
Isomer
Simple isometric graphics library for HTML5 canvas
Html2canvas
Screenshots with JavaScript
Responsive Img
Responsive Img is a jQuery plugin that changes an image's src attribute based on its container's width.
Tremula Js
TremulaJS: Picture Streams + Momentum Engine + Bézier Paths + Multi-Device
jQuery QR Code
qrcode generation standalone (doesn't depend on external services)
Jcrop
Jcrop (official) - Image Cropping Plugin for jQuery
Processing.js
A port of the Processing visualization language to JavaScript.
Raphael
JavaScript Vector Library
Scenejs
An extensible WebGL-based engine for high-detail 3D visualisation
Photoset Grid
A simple jQuery plugin to arrange images into a flexible grid, based on Tumblr's photoset feature.
Lightslider
JQuery lightSlider is a lightweight responsive Content slider with carousel thumbnails navigation
Beerslider
A vanilla JS keyboard accessible plugin for any before-after comparison
Svg.js
A lightweight library for manipulating and animating SVG
Sylvester
Vector, matrix and geometry math JavaScript