Bootstrap Zero - Open-source, free Bootstrap templates collection.
Volt - Volt is a reactive web framework where Ruby code runs both on the server and the client (via opal).
Bootstrap Magic - Create your Bootstrap 4.0 themes easily with magic
HandL - Label data for machine learning with ease
Material Design for Bootstrap 4 - Powerful and free UI KIT for the newest Bootstrap 4 and Material Design
Wedio - Your Local Camera Sharing Community