You can play many ROMs on a single emulator. Overall, emulators represent a gaming console and ROMs represent the game. They contain all the game data and files needed to play retro games. Roms are the specific game files which can be played by an emulator. And with a little reading time and customization effort, you can play classic retro games in your VR headset.
Since the Oculus Quest is an Android-based VR headset, it has native support for many Android emulators available today. With an emulator, you can play old Pokemon, Mario, and other games on your TV. They are popular for playing classic retro games in 2021.