Stylebot - Change the appearance of websites instantly. Preview and install styles created by other users on stylebot.me
Amino Editor - Amino is a Chrome browser extension for customizing web page presentation with user CSS.
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.
Stylus - User Styles Manager - Stylus is a userstyles editor and manager based on the source code of Stylish version 1.5.2.
xStyle - A user styles manager for the Web
Stylus - EXPRESSIVE, DYNAMIC, ROBUST CSS