Overmind
Overmind - Frictionless state management
Backbone.stickit
Backbone data binding, model binding plugin. The real logic-less templates.
JsRender
A light-weight but powerful templating engine, highly extensible, without DOM or jQuery dependency.
Machina.js
js ex machina - finite state machines in JavaScript
Nanobar
Very lightweight progress bars. No jQuery
Sift.js
filter arrays using mongodb queries
Montage
Core framework: Montage simplifies the development of rich HTML5 applications by providing modular components, real-time two-way data binding, CommonJS dependency management, and many more conveniences. Join us on irc.freenode.net#montage or https://groups.google.com/d/forum/montagejs
Almond
A minimal AMD API implementation for use after optimized builds
Curl
A small, fast module and resource loader with dependency management. (AMD, CommonJS Modules/1.1, CSS, HTML, etc.)
Blazy
bLazy is a lightweight lazy loading and multi-serving image script. It's written in JavaScript why it doesn't have any dependencies for 3rd party libraries like jQuery. bLazy is working in all modern browser including IE7+.
Simplecart
A simple javascript shopping cart that easily integrates with your current website.
Backbone Layout Manager
A layout and template manager for Backbone.js applications.
Across Tabs
Easy communication between cross-origin browser tabs
Humane.js
A simple, modern, browser notification system
React Templates
Light weight templates for react
Webshim
Webshims Lib is a modular capability-based polyfill-loading library
Visibility.js
Visibility.js allows you to determine whether your web page is visible to a user, is hidden in background tab or is prerendering. It allows you to use the page visibility state in JavaScript logic and improve browser performance by disabling unnecessary timers and AJAX requests, or improve user interface experience (for example, by stopping video playback or slideshow when user switches to another browser tab).