Dropzone
Dropzone is an easy to use drag'n'drop library. It supports image previews and shows nice progress bars.
Angular.js
AngularJS lets you write client-side web applications as if you had a smarter browser. It lets use good old HTML (or HAML, Jade and friends!) as your template language and lets you extend HTML’s syntax to express your application’s components clearly and succinctly
RequireJS
A file and module loader for JavaScript
Dc.js
Multi-Dimensional charting built to work natively with crossfilter rendered with d3.js
Sweetalert
A beautiful replacement for JavaScript's "alert"
iScroll
Smooth scrolling for the web
Slideout
A touch slideout navigation menu for your mobile web apps.
Rickshaw
JavaScript toolkit for creating interactive real-time graphs
Nprogress
For slim progress bars like on YouTube, Medium, etc
Local Forage
Offline storage, improved. Wraps IndexedDB, WebSQL, or localStorage using a simple but powerful API.
Csscomb.js
CSS coding style formatter
Bootstrap Calendar
Full view calendar with year, month, week and day views based on templates with Twitter Bootstrap.
Tock
Timer Object/Class. Kickass!
Ani X
Super easy and lightweight css animation library
Redhooks
Predictable state container for React apps written using Hooks
jQuery Backstretch
Backstretch is a simple jQuery plugin that allows you to add a dynamically-resized, slideshow-capable background image to any page or element. The image will stretch to fit the page/element, and will automatically resize as the window/element size changes.