Gitscout - A beautiful Github Issues experience for macOS
Stylebot - Change the appearance of websites instantly. Preview and install styles created by other users on stylebot.me
Zokyo - GitHub Chrome Extension to track and manage issues
Amino Editor - Amino is a Chrome browser extension for customizing web page presentation with user CSS.
GitHub Reader - A quick way to browse GitHub issues and pull requests.
Stylus - User Styles Manager - Stylus is a userstyles editor and manager based on the source code of Stylish version 1.5.2.