Persist State
jQuery Ui widget that will transparently save the state of checkboxes, inputs, selects, etc in localStorage, restoring these on the user's next visit to the page.
Kimbo.js
An ECMAScript 5 only-compatible JavaScript library.
Fragment.js
A tiny tool for easily loading html fragments and templates
Elements
E+lements is a minimal DOM Library for the prime framework.
Porthole
A proxy to safely communicate to cross-domain iframes in javascript
Eqcss
EQCSS is a plugin that introduces Element Queries, Scoped CSS, a Parent selector, and responsive JavaScript to all browsers IE8 and up
jQuery.lazy
A lightweight, fast, feature-rich, powerful and highly configurable delayed content, image and background lazy loading plugin for jQuery & Zepto.
Double
jQuery plugin for hiring doubles
jScrollPane
Pretty, customisable, cross browser replacement scrollbars
Responsive Comments
A client-side solution to conditional loading.
Viewport
Gets the dimensions of the Viewport and beyond.
jQuery Evergreen
Small & fast DOM and event library for modern browsers.
Node List.js
NodeList implementation/library - Use the Native DOM APIs as easily as jQuery
Veinjs
Injects CSS into the document (it's a perfectly legal procedure)
Tether
A positioning engine to make overlays, tooltips and dropdowns better #hubspot-open-source
Resize Observer
Polyfills the ResizeObserver API.
Design Blocks
A set of 170+ Bootstrap based design blocks ready to be used to create clean modern websites.