Dr. Link Check - Broken link checker with malware and parked domain detection
Stylebot - Change the appearance of websites instantly. Preview and install styles created by other users on stylebot.me
BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
FreeStylerWs - Styles and skins for all popular sites in the web
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Stylem - A user style manager for Pale Moon, Basilisk, Interlink, SeaMonkey, and other Mozilla-based software. Install styles from userstyles.org to change how web pages and the application look.