I'm 52 years old so I can remember even before Atari 2600 came out my dad had a dedicated console that connected to the TV and I think all it had was Pong, maybe a few others. I believe it was called Pong IV.
So I think it would be some type of pong.
Around that same time, maybe just a little while later, we got a 2600 and it was Combat and Gunslinger.