Porthole
A proxy to safely communicate to cross-domain iframes in javascript
Tippyjs
Highly customizable vanilla JS tooltip/popover library
Elements
E+lements is a minimal DOM Library for the prime framework.
Fastdom
Eliminates layout thrashing by batching DOM read/write operations
Asm Dom
A minimal WebAssembly virtual DOM to build C++ SPA (Single page applications)
Html
A simple, extensible way to work directly with the DOM.
Zest
An absurdly fast CSS selector engine.
React Virtualized
React components for efficiently rendering large lists and tabular data
Packery
bin-packing layout library
Mag.js
MagJS - Modular Application Glue
Voyeur.js
Voyeur is a tiny (1.2kb) Javascript library that lets you traverse and manipulate the DOM the way it should have been.
Phantomjs
Scriptable Headless WebKit
Reseter.css
Reseter.css - A Futuristic Alternative To Normalize.css And CSS Resets
Kimbo.js
An ECMAScript 5 only-compatible JavaScript library.
Eqcss
EQCSS is a plugin that introduces Element Queries, Scoped CSS, a Parent selector, and responsive JavaScript to all browsers IE8 and up
Interact.js
Drag and drop, resizing and multi-touch gestures with inertia and snapping for modern browsers (and also IE8+)
Scrob Master
Master your scroll events.