Meld
AOP for JS with before, around, on, afterReturning, afterThrowing, after advice, and pointcuts
Hamsters.js
100% Vanilla Javascript Multithreading & Parallel Execution Library
Theory
Abstraction layer for cross platform JavaScript.
Loglevel
Minimal lightweight logging for JavaScript, adding reliable log level methods to wrap any available console.log methods
Jquerypp
jQuery's missing utils and special events
Backbone Nested
A plugin to make Backbone.js keep track of nested attributes.
Tweet
put twitter on your website with tweet, an unobtrusive javascript plugin for jquery
Eve.js
A <3kb JavaScript file providing three simple methods to organize code into CSS namespaces which magically restrict code to the current context, allowing for dramatic reductions to code size and development time.
Min Pub Sub
198 byte publish/subscribe messaging micro-framework
JayData
JayData is a unified data access library for JavaScript to CRUD data from different sources like WebSQL/SQLite, IndexedDB, MongoDb, ASP.NET WebAPI, OData, HTML5 localStorage, Facebook or YQL. The library can be integrated with KendoUI, Knockout.js, Handlebars.js or Sencha Touch 2 and can be used on Node.js as well.
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.
Routie
a tiny javascript hash router
Functional Js
A functional js library that facilitates currying and point-free / tacit programming
Robotjs
Node.js Desktop Automation.
Fluxxor
Flux architecture tools for React
Invisible
Invisible.js: Reusable models for the client and the server
Fetchival
window.fetch wrapper for writing simple and expressive requests