The WorkBoy, a cancelled add-on for the Game Boy, 1992

The accessory would have connected to the Game Boy via its link cable port and transformed it into a personal digital assistant (PDA) with features like a calendar, calculator, and address book. It was cancelled because the unit was too expensive and would have cost as much as the Game Boy itself whose price was recently lowered around the time.

WorkBoy: Lost Game Boy Add-on FOUND After 28 Years