jQuery.masterblaster is a nice and tidy tag manager.    

jQuery Tooltipify plugin creates a slide in, stylable tooltip to replace the default browser tooltip. The show and hide events are customizable.  This tooltip plugin has display awareness and also responds to the window resize event. It supports html content by using the content property.    

AutoJS is a library to continuously autocomplete textarea based on a standard dictionary. Dictionary has been deviced based on researches and linguistic methods, keeping an eye on minimizing the size of the library. Complete project is written in plain js, with no external dependencies, and it's size is reduced to mere 6kb.    

Tag Manager is a jQuery plugin to create tag input fields, which works nicely with Twitter Typeahead.js and Twitter Bootstrap.    

Bootstrap Tour makes it quick and easy to build your product tours with Twitter bootstrap popovers.    

PowerTip features a very flexible design that is easy to customize, gives you a number of different ways to use the tooltips, has APIs for developers, and supports adding complex data to tooltips. It is being actively developed and maintained, and provides a very fluid user experience.    

Simpletoolip is a Jquery plugin, thought to insert short tooltips to any element of your website more easily.   Simpletoolip - Features: Jquery based Minimal configuration 12 functional positions no extra html structures, use "title" attribute cross-browser lightweight and fast download, less than 8Kb    

jQuery Open Carousel is an open and easy to implement carousel display made using jQuery. It supports linking to scroll to any slide, automatic generation of indicator circles, and pretty much any content will work inside of it. Multiple carousels can exist on one page without conflict. Many configuration options can be set dynamically using data attributes.    

blueimp Gallery is a touch-enabled, responsive and customizable image & video gallery, carousel and lightbox, optimized for both mobile and desktop web browsers. It features swipe, mouse and keyboard navigation, transition effects, slideshow functionality, fullscreen support and on-demand content loading and can be extended to display additional content types.    

Conveyor-Belt is a simple but well adjustable slideshow carousel jQuery plugin. There are plenty of configurations available, including transition types, image fits and slideshow speeds.