JavaFX is not just the API you get from the installation. There is a large range of libraries, frameworks, and technologies created by third-party developers.
There is a great list of such items at https://github.com/mhrimaz/AwesomeJavaFX. There are dozens of entries there, so I'll list the ones I consider to be the most interesting next.