Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
Helix Ultimate a free template framework for Joomla.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Typekit is an online service which offers a subscription library of fonts.