Nice video! I personally own an IntelliVision System Changer. Came bundled with my Mattel IntelliVision 2 as a nice surprise which wasn't mentioned in the description. It served as my first Atari VCS/2600 original hardware before I got my Atari 7800.
Great stuff lad. I had the Atari expansion for my ColecoVision it worked but it was clunky. Also, it wasn't quite as reliable as advertised, which for the time, was expected.
Hey, I learnt something new, the only one I knew of is the Colecovision Atari 2600 module. The Telegames Personal Arcade is kind of like a predecessor to the FC Twin and Retron series of consoles in a way.
There was also an atari adaptor for the C64 to allow you to play atari 2600 games on the C64 and there was also a rumored gamegear adaptor for the atari lynx to play gamegear games on the atari lynx.