Adds &fmt=18 to the url for high quality but not if any &fmt=x already exist

Several customizable options. Special support for Userscripts.org (new interface, fix for pre tags, and allows you to hide the install warning box and footer) Changes text fields, buttons, links, selects, and text areas.

Take youtube back, force it to use worldwide contents!

Prevents videos from playing automatically. Edited by JoeSimmons to play the high quality version instead of the normal. Option added to use the old or the new player.

Adds MP4 and FLV download links to YouTube

Food your stats Monkey! This script adds differences (if any) to Youtube My Account details. Also supports youtube.com multiple accounts.

Adds &fmt=18 to all YouTube links

Customize YouTube's Player Page

Shows an HQ link by the description of a video

Strips YouTube's interface down to a bare nothing and optimizes load time.

Switches to YouTube's HQ version quickly (no reloading)

Adds a link and userscript command to search a page and highlight the result

Blue theme for YouTube. Changes nearly everything to blue... even the icon. Several customizable options just like in Web Styler. Check the screenshot.

Watch videos in high quality automatically. Now has a UserScript command to toggle a confirmation box. Made for people who don't login or save cookies. Uses JavaScript instead of &fmt=18; no reloading pages

200% YouTube video size.

Adds a set of links on small images.