tubebaddy extension

Forces Adobe Flash to use HTML5 video player.

Online password manager and form filler.

Saves the content of web forms in progress.

Delete elements from a web page.

Save and run arbitrary bits of JavaScript code.

Add search engines to Safari.

Extension for Mozilla/Thunderbird that integrates with GnuPG.

Extension to the OS X color picker panel.

Add, remove, or change file name extension.

Safari extension that controls which scripts—and more—run on websites.