Select2 : Select2 is a jQuery based replacement for select boxes. It supports searching, remote data sets, and infinite scrolling of results.
Sammy.js : Sammy is a tiny javascript framework built on top of jQuery, It's RESTful Evented Javascript.
jquip : Smaller, Lighter, Faster, more modular jQuery - include only the parts you want! Don't use it, Don't include it.
hoverIntent jQuery Plug-in : hoverIntent is a plug-in that attempts to determine the user's intent... like a crystal ball, only with mouse movement! It is similar to jQuery's hove...
Morris.js is a lightweight library that uses jQuery and Raphaël to make drawing time-series graphs easy.