A long-gone unreleased accessory for Game Boy called WorkBoy was discovered after 28 years. The accessory was meant to grant access to new apps like calculator, address book, and such.
There are only 1-2 known prototypes of WorkBoy from those years left, and video game historian Liam Robertson managed to get one of those in his hand. Shared his story on YouTube on the channel DidYouKnowGaming?
WorkBoy was basically a keyboard that would grant you access to 12 new apps upon connection.
WorkBoy was trademarked by Nintendo of America and was in the spotlight in CES 1992, but due to various reasons, it never got released. The accessory would cost around $79-$89 if it got its place on shelves, but that didn’t happen and in early 1993 the project was scrapped.