Chromium OS is the open-source version of Google's closed-source Chrome OS that is only available on Chromebooks.
Remember the performance of macOS, particularly graphical support is very limited on a virtual machine so performance with graphical animations will be subpar compared to a real mac or hackintosh, but it will still get the job done. Whether you want to try out macOS, run Xcode or make a hackintosh you can use a virtual machine to get started on macOS.
