I have enabled beta devices in Vivado, but when I open the compile_simlib help menu I only see these device families available:
How do I compile simulation libraries for beta devices and UltraScale+?
To get a complete list of valid device families you can input an invalid family name as seen below and you will get an error message stating the valid device families:
compile_simlib -family test
The above list includes the valid beta devices for Vivado 2015.4.
New devices will be added to the compile_simlib menu in a later release of Vivado.