Mailcheck
Email domain spelling suggester
Dicebear
DiceBear is an avatar library for designers and developers.
ES5 Shims
ECMAScript 5 compatibility shims for legacy JavaScript engines
Device.js
Device.js makes it easy to write conditional CSS and/or JavaScript based on device operating system (iOS, Android, Blackberry, Windows, Firefox OS), orientation (Portrait vs. Landscape), and type (Tablet vs. Mobile).
Vex
A modern dialog library which is highly configurable and easy to style. #hubspot-open-source
LZ String
LZ-based compression algorithm for JavaScript
G2 Plot
:dango: An interactive and responsive charting library
Hello.js
A Javascript RESTFUL API library for connecting with OAuth2 services, such as Google+ API, Facebook Graph and Windows Live Connect
Framer
Modern Prototyping Tool
Loki JS
javascript embedded / in-memory database
Kendo Ui Core
Kendo UI Core
Lightgallery.js
Full featured javascript lightbox gallery. No dependencies.
Remarkable
Markdown parser, done right. Commonmark support, extensions, syntax plugins, high speed - all in one.
Stream Saver.js
StreamSaver writes stream to the filesystem directly asynchronous
Metrics Graphics
A library optimized for concise, principled data graphics and layouts.
Jquery Transit
Super-smooth CSS3 transformations and transitions for jQuery
Jquery Timeago
Timeago is a jQuery plugin that makes it easy to support automatically updating fuzzy timestamps (e.g. "4 minutes ago").