It actually has official builds for almost 250 devices from 29 different brands, and there are a lot more unofficial builds that work as well as the official ones. The number of devices is constantly expanding, too.
By the way, Samsung is probably the worst phone to choose. The custom ROM can only be loaded on the Exynos variants (i.e. non-U.S.), and after installation, they can’t implement VoLTE, which is mandatory for activating a phone on U.S. networks, and is starting to be needed in many other countries, too, as they shut down 3G networks.
(Samsung’s IMS/VoLTE software is proprietary and can’t be implemented in a custom ROM, apparently.)