Pegasus
Load data while still loading other scripts and display data faster in jQuery, Backbone, Angular, ... apps
Hasher
Browser history manager for rich media websites
Stapes
a (really) tiny Javascript MVC microframework
Prime
an OOP javascript library for node.js and the browsers
Jsface
Small, fast, elegant, powerful, and cross platform JavaScript OOP library. Support main(), singleton, super call, private, mixins, plugins, AOP and more.
Thinkjs
Use full ES2015+ features to develop Node.js applications, Support TypeScript.
Lunr.js
A bit like Solr, but much smaller and not as bright
jTypes
jTypes is the most comprehensive and robust JavaScript library for overcoming differential inheritance with prototype-based objects. Its lightweight yet powerful design provides web programmers on any platform or browser the ability to emulate classical inheritance where objects are defined by classes.
Hermes.js
Message and Error logger implementation
Mask Js
Zen Coding | Markup | Template | HMVC
Lazy Load Xt
Lazy load XT is a jQuery plugin for images, videos and other media
Aura
A scalable, event-driven JavaScript architecture for developing widget-based applications. Works with Backbone.js and other frameworks.
Scale App
scaleApp is a JavaScript framework for scalable One-Page-Applications
101
A modern JS utility library
YUI3
YUI is a free, open source JavaScript and CSS library for building richly interactive web applications.
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.
Weld
Template antimatter for Node.js (Browsers too!)