Dc.js
Multi-Dimensional charting built to work natively with crossfilter rendered with d3.js
Loaders.css
Delightful, performance-focused pure css loading animations.
Wow
Reveal CSS animation as you scroll down a page
Noty
noty - jquery notification plugin
Tether
A positioning engine to make overlays, tooltips and dropdowns better #hubspot-open-source
Pdfkit
A JavaScript PDF generation library for Node and the browser
Chai
BDD / TDD assertion framework for node.js and the browser that can be paired with any testing framework.
Wavesurfer.js
Navigable waveform built on Web Audio and Canvas
Robotjs
Node.js Desktop Automation.
Respond
A fast & lightweight polyfill for min/max-width CSS3 Media Queries (for IE 6-8, and more)
List
Do you want a 3 KB (gzipped&minified) cross-browser native JavaScript that makes your plain HTML lists and tables super flexible, searchable, sortable and filterable? Yeah! Do you also want the possibility to add, edit and remove items by dead simple templating? Hell yeah!
Easel JS
The Easel Javascript library provides a full, hierarchical display list, a core interaction model, and helper classes to make working with the HTML5 Canvas element much easier.
Cropperjs
JavaScript image cropper.
Headroom.js
Give your pages some headroom. Hide your header until you need it
Peerjs
Peer-to-peer data in the browser
Matter JS
a 2D rigid body physics engine for the web