Userscripts.org

Show the favorite items (e.g. Wikipedia entries) at the top of the Google search result.

Hides questions on the home page and main question list which have certain uninteresting tags, unless they also have some interesting tags

Enhances http://stackoverflow.com, http://meta.stackoverflow.com, http://superuser.com, and http://serverfault.com.

Add reply links to comments

This userscript will switch the comment text box and preview area so that the preview area is above the text box area.

StackPrinter - The Stack Exchange Printer Suite.

Let Commander Keen do the downvoting

Adds a tab to the Stack Overflow navigation that shows most recent interesting questions

Adds embedded jsFiddle content to the questions/answers posts.

Show threaded comments on Stack Overflow and other Stack Exchange sites

Drag and Drop Tags to add them to the Ignored/Interesting lists

Makes the stackoverflow top bar stay fixed to the top of the window and shrink when scrolled down.

This userscript will add a 'question' tag to delicious bookmarks when you save them.

This userscript will add a 'stackoverflow' tag to delicious bookmarks for stackoverflow.com, when you save them.

Give the user the choice which language to use for syntax highlighting

This userscript will update the ask a question form on StackOverflow to use @placeholder, instead of their wacky junk.

This userscript will hide job ads at Stack Overflow.

Try to guess alignment of RTL posts on the Stack Overflow Chat

This userscript will remove the redunant x's beside tag names in StackOverflow's right nav.

For http://meta.codereview.stackexchange.com/q/33/697

Plays a sound when a new question is detected that matches your interesting tags. Also refreshes the page constantly so that you can be automatically notified.

This script allows you to collapse or hide deleted answers on StackOverflow

Adds unread questions counter to favicon

Replaces dull voting arrows on Stack Overflow with something more appropriate.

Configurable helper to enable a quicker retagging of questions at Stack Overflow

Enables the "View vote counts" feature on the Stack Exchange websites, without requiring any reputation or an account.

prevents the "Welcome" bar from popping up on StackExchange sites (stackoverflow.com, serverfault, etc.)

Searchbox for searching through the answers on the current question