Userscripts.org

this script does some modifications on 4fuckr.com as you hover the picture thumbnails on the site you will see them in a full size tooltip

Display tooltip with movie or game info when hovering compatible links

*BETA* - Removes tooltips and GCVote-stars of invisible caches on the new map.

Instead of an 'in reply to [someone]' link on twitter, see the actual tweet in a tooltip

Displays the graph's value at the current cursor position

Adds tool tips to Images so you can view their translated description / alt-text easily

Translate words on a webpage from Hebrew to English and vice-versa in little tooltips

Converts specific text strings to links to the corresponding pages with preview tooltips.

Displays a tooltip for YouTube videos with video information and a small player for a preview.(English/German)

Sets email subject and snippet tooltips.

Autoloads for next page of Google Images search results & Enables the images to be embeded in a preview tooltip.

Improves the info tooltips of thumbnails (makes them look prettier and adds further information).

Displays info tooltips on the thumbnail images on pixiv.

Auto Translate Words on a Webpage

Forces display of tooltip previews in vBulletin thread lists, even if the original poster attempted to obsfucate their content by eg. wrapping it in quote BBCode.

Puts alt text or source filename in image title attribute, if title is empty.

Shows passwords on mouse hover or focus

Expand shortened URLs (i.e. TinyURL.com, is.gd, bit.ly, etc.) wherever you go by harnessing the power of LongURL.org.

Adds tooltip for references to Slashdot articles

Add Scripture tooltips from any online Bible to any Bible reference

Displays Jyte claim descriptions in a tooltip when mousing over a claim.

Advanced website usability script that makes more or less fancy tooltips out of standard title attributes!

Shows the "hover text" for some comics on the page

This script makes image alt text appear in tooltips when the mouse hovered over it.

dict.cn 利用dict.cn的服务，给浏览器页面添加划词搜索功能

script to add the title attribute to images (based on the alt-attribute)

Reveals destination URLs hidden by snipurl( www.snipurl.com)

Reveals destination URLs hidden by TinyURL

Show character count when mouseover on textarea

Enables support for multiline tooltips in Firefox (works in Firefox 1.5+)