Bootstrap 4 Cheat Sheet - An interactive Bootstrap 4 cheat sheet
Darkmode Widget - Add a dark-mode to your website in a few seconds 🌓
Bootstrap Zero - Open-source, free Bootstrap templates collection.
Dark Mode List - A list of apps that support 🌃 dark mode
HackerThemes - Bootstrap 4 themes and tools for web developers
Nebular - UI kit & Design System for web with light/dark mode support