jKit (GitHub: FrediBach / jQuery-jKit, License: MIT) by Fredi Bach is a relatively small (47 KB) UI toolkit. It can work with data attributes, so adding
data-jkit attributes to the relevant elements will invoke various components.
There are a lot of effects and components, including tooltips, charts, parallax scrolling, and a lightbox. The project has detailed documentation on each of the bundled plugins, and a simple introduction for non-programmers.
Coincidentally, Dimitar Ivanov also sent in a UI toolkit of sorts: the ZinoUI Framework (License: CC BY-NC 3.0). This framework requires commercial licensing starting at $50 per site, and includes advanced widgets more comparable to jQuery UI, like a calendar and tree view.
ZinoUI is WAI-ARIA compatible, so may suit projects with stricter accessibility requirements. It has been tested with Google Chrome 12+, Firefox 4+, Safari 5+, Opera 11+, and IE8+.
jQuery.ajax.fake (GitHub: anasnakawa / jquery.ajax.fake, License: MIT, component:
anasnakawa/jquery.ajax.fake) by Anas Nakawa can be used to mock jQuery
$.ajax calls. A mocked call will be made when passing
fake: true as an option to
$.ajax. It can be disabled globally, and works with deferred calls.