Lubuntu is a fast and lightweight operating system with a clean and easy-to-use user interface. It is a Linux system, that uses the minimal desktop LXDE/LXQT.
Google Chrome OS is a Linux-based operating system designed by Google that uses the Google Chrome web browser as its principal user interface, so it works primarily with web applications.
Chromium OS is an open-source project, used primarily by developers, that aims to build an operating system that provides a fast, simple, and more secure computing experience for people who spend most of their time on the web.
GalliumOS is a fast and lightweight Linux distro made for Chromebooks and Chromeboxes. GalliumOS delivers a complete Linux environment with full hardware support, a carefully tuned kernel, and a full-featured and attractive desktop.