CSS Scan - Instantly check or copy computed CSS from any element for only ~95$
Stylebot - Change the appearance of websites instantly. Preview and install styles created by other users on stylebot.me
EazyCSS - No code CSS editor for any website.
Dark Reader - Reduce eye strain in your browser with this extension that provides a dark theme for browsing.
Hoverify - All-in-one browser extension to improve your web dev experience.
Stylus - User Styles Manager - Stylus is a userstyles editor and manager based on the source code of Stylish version 1.5.2.