Hover-Over-Popups, CSS/XHTML-friendly, see also http://www.nicolashoening.de/?twocents&nr=8
Avgrund is jQuery plugin with new modal concept for popups
Light and responsive lightbox script with focus on performance.
A modal dialog box plugin for jQuery
A jQuery tooltip plugin
Fast & light modal popup creator providing rich configuration and styling
Generate CSS tooltip arrows
bPopup is a lightweight jQuery modal popup plugin (only 1.34KB gzipped). It doesn't create or sty...
Tooltip popup for jQuery
An alternative to original alert, confirm and prompt.
Reactjs component for spawning custom popups at mouse position.
hint.css by jQuery
jBox is a jQuery plugin that makes it easy to create customizable tooltips, modal windows, image ...
A prototype/lowpro based Facebook-style windowing solution
Popline is an HTML5 Rich-Text-Editor Toolbar