I made these things. You might enjoy them.
A ridiculously easy-to-use PHP script for resizing images the smart way.
Search Amazon the smart way–with search suggestions as you type.
Joe Lencioni’s Greased Lightbox is a Greasemonkey, GreaseKit, and Opera user script designed to enhance browsing on websites that link to images such as Google Image Search, Flickr, Wikipedia, MySpace, deviantART, and FFFFOUND!.
Justified text on the web is almost always a bad idea. Unjustify will let you zap it. Nice.