There's a custom board with modern electronics for the Sega game gear, basically sega's answer to the game boy black and white
Ah, the Game Gear. When through batteries like Charlie Sheen on a coke binge and while it technically did have a color display, it was like the worst cheapest passive matrix garbage panel imaginable. If that wasn't bad enough, the library of games kind of sucked, too.
If that "we have X at home" meme was a thing back then, Game Gear would've had one. I'm sure by now though, there's at least a few of us olds who fondly remember playing a bad port of Sonic the Hedgehog instead of finishing their homework. I wasn't one of those spoiled kids though; it took a lot of begging just to get my folks to finally buy me a NES. Even then, my games library was more-or-less the local VHS rental joint.
An iPad or Android tablet with a screen you can actually see and boatloads of free-to-play games, is the real innovation since then.