Userscripts.org

Enhances YouTube's HTML5 player. Some features: additional keyboard shortcuts (including navigation); fix player bugs; control autoplay and auto fullscreen; informational text overlay on video. Customizable (except for the key shortcuts).

Adds a display of the total duration, and a count, of all your YouTube subscriptions.

Prevents YouTube's Character Counter from Becoming Active through the Tab Key

[DISCONTINUED - Please use YouTube Center instead] Properly center align YouTube's layout on every page.

Brings back the old Youtube search/sort options on the video filters, which were removed from Youtube with the new design in December 2012. The script also expands the main layout column to fit these new options.

mouseover to animate thumbs

Dec. 10, 2012 - UPDATED! Fixes for new YouTube layout and changes to how MP3's are downloaded!

Brings the inbox overview back to the home page

Shows videos by the same user

Adds the national flag icons next to each username in the comment section of Youtube.

Show video ratings on Youtube

This script makes video recommendations, search results etc. from youtubers you don't like go away.

Shows the rating of videos in their thumbnails

Adds a download menu to YouTube videos.

Moves the video to the top of the website and resizes it to the screen size. A side effect is that the resolution will auto-select 480p/720p/1080p if it fits in the window due to the video player's default behaviour.

Scrobbles the currently watching YouTube video to Last.fm manually and automatically.

Removes the annoying tracking parameter called "feature" from links on YouTube. (&feature=related and ~25 others) All your YouTube links will follow the same pattern. No unnecessary information in URLs.

Shows the number of times a video has been liked/disliked, without having to (dis)like it.

See a selection of other videos from the uploader of the video you are watching.

Makes YouTube videos large. As well as rearranges the terrible new YouTube layout into an elegant layout that has great functionality and I've added a nice lights-out feature to darken the outside screen to give you more focus on the video. Enjoy!...

In with the Old, Out with the New (YouTube)

Jan 15 2013 Major update - now really #1 script of its kind! This script modifies video links on the page with an extra parameter that adds a sleek list of 'More Videos From' (up to 99 videos) the same uploader. FF&Chrome (see screenshot)

Download videos from video sharing web sites.

Changes javascript links into direct links

Removes Video-Sidebar from Youtube homepage, maximise the width of the homepage content on old good template of youtube and automatically display all videos

YouTubeの動画の各コメントに国旗アイコンを表示する / Adds the national flag icons to each video comments in YouTube.

Automatically set video quality to max!

Removes annoying Google+ pop-up from YouTube.

Changes the quality setting of flash files.

Resizes the video to a nice and comfortable size unlike other resizers. Autoscrolls to the player and also hides youtube guide and puts the title on top centred. WORKS WITH THE NEW LAYOUT!! (1/2/2012) with 21/3/2013 FIX