Dark Reader - Reduce eye strain in your browser with this extension that provides a dark theme for browsing.
Slack Themes - Make your Slack pretty with custom themes
Night Eye - Night Eye is a browser extension that enables dark mode on any website you visit. It does not ruin your browsing experience by simply inverting images.
Branded Slack Themes - 1,000+ themes to customize your Slack
Dark Mode - A global dark theme for the web
Rainglow Color Themes - 320+ color themes for a variety of editors and software.