1. Google closures library → code.google.com/closure/library
2. MooTools → mootools.net
3. YUI → developer.yahoo.com/yui
4. dojo → dojotoolkit.org
5. jquery → jquery.com

autres exemples :

1. lightbox2
2. script.aculo.us
3. moo.fx
4. curvycorners.net