Adblock
From MozillaZine Knowledge Base
Adblock is an extension for Firefox and Mozilla Suite. It can hide graphics on pages, block them from ever loading, block JavaScript files, embedded frames (IFRAMEs), and Flash movies. It uses wildcards and regular expressions to match files to block. The following is a list of example filters for Adblock.
Blocks ads in any directory called "banner", "banners", or any case insensitive equivalent:
/\Wbanners?\W/
Blocks ads in any directory called "ad", "ads", or any case insensitive equivalent:
/\Wads?\W/
Blocks ads on Yahoo!:
/yimg\.com(.*/adv/|/a[^u])(?!vision)/
Additionally, there are several filtersets available online such as the popular Filterset.G and FiltersetP