Modernizr
Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.
Fast.js
Faster user-land reimplementations for several common builtin native JavaScript functions.
Js Cache
jsCache is a javascript library that enables caching of javascripts, css-stylesheets and images using my localStorage polyfill. This is especially useful when serving your website for mobile phones, which have limited HTTP caching available, but also speeds up your site in an ordinary web browser as it saves HTTP requests and loads all files asynchronously.
Davis.js
RESTful degradable JavaScript routing using pushState
Rambda
Faster alternative to Ramda in just 10kB
Queen
A platform for running scripts on many browsers
Stately.js
Stately.js is a JavaScript based finite-state machine (FSM) engine for Node.js and the browser.
Min Pub Sub
198 byte publish/subscribe messaging micro-framework
ifvisible.js
Checks if the current page is visible or not
P
Peer-to-peer networking with browsers
Mousetrap
Simple library for handling keyboard shortcuts in Javascript
Jquery Timeago
Timeago is a jQuery plugin that makes it easy to support automatically updating fuzzy timestamps (e.g. "4 minutes ago").
Pilot
Pilot — multifunction JavaScript router.
Gas
Google Analytics on Steroids. A Google Analytics implementation with more power features.
Buster
A powerful suite of automated test tools for JavaScript.
Boiler
Boiler is a utility library that makes every day tasks in JavaScript easier by providing over 115 methods that work on arrays, collections, functions, numbers, objects, and strings.
Knockout Projections
Knockout.js observable arrays get smarter