Loaders

• html5-preloader
• JSL
• LABjs
• yepnope.js
• head.js
• ControlJS
• load.js
• $script.js
• lazyload
• DeferJS - Contains also a jQuery specific version.
• jQI
• YUI 3: Get
• dominatejs
• bootstrap
• StealJS
• DominateJS
• BravoJS
• NBL.js
• Hydra.js
• includejs

AMD

These libraries conform to the AMD module definition.

• RequireJS
• curl
• loader-js
• bdLoad
• almond - A minimal AMD API implementation for use after optimized builds.

Other

• JavaScript Loader Comparison (Google Doc Document)
• Reddit - How do you guys build your js files for deployment?