spin.js
CSS3 Loading Animation Loop
CSS3 Loading Animation
CanvasLoader Creator
Flickr Style Loading Animation Using JQuery
CSS Loading Animation Circle Style
Loading CSS spinners and bars generator for AJAX & JQuery
Ajax Style Loading Animation in CSS3 (no Images)
CSS3 loading spinners without images
Bouncy Animated Loading Animation
Sonic – looping loaders
Simple Loading Modal
PageLoading – jQuery plugin
Image Loader (jQuery Plugin)
Simple Content Loader
Preloadify
Source: http://designmodo.com/css3-jquery-loading-animations/