Webpack
Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jade, coffee, css, less, ... and your custom stuff.
Almond
A minimal AMD API implementation for use after optimized builds
Aload
Loads images, scripts, styles, iframes, videos and audio asynchronously.
Lazyload
Tiny, dependency-free async JavaScript and CSS loader.
Lazy Load Xt
Lazy load XT is a jQuery plugin for images, videos and other media
LABjs
Loading And Blocking JavaScript: On-demand parallel loader for JavaScript with execution order dependencies
Sea.js
A Module Loader for the Web
Script.js
Asyncronous JavaScript loader and dependency manager
Lazysizes
High performance and SEO friendly lazy loader for images (responsive and normal), iframes and more, that detects any visibility changes triggered through user interaction, CSS or JavaScript without configuration.
Pilpil
Pilpil - Progressive Image Loading
Imagesloaded
JavaScript is all like "You images done yet or what?"
Nanobar
Very lightweight progress bars. No jQuery
Layzr.js
A small, fast, modern, and dependency-free library for lazy loading.
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+.
jQuery Pjax
pushState + ajax = pjax
RequireJS
A file and module loader for JavaScript
Query Loader2
Version of the QueryLoader by Gaya Design. Preload images with ease.