Darker Medium applies a customizable dark theme to *all* medium formatted stories. You can customize the header background, main accent color, highlight color and link styles separately from the option menu. No matter the domain, if a site is using Medium, it will get a dark theme; that is the main advantage over Stylus and Stylish.
Darkness is a Chrome extension that provides dark themes for popular websites
Darkdocs adds a dark mode to your Google Docs writing experience.
Dark Mode List is a list of apps and sites that support dark mode