Now here is something really cool. Fooni on the REGN8 Discord server announced that he and a team are currently working on a multiplayer mod for The Legend of Zelda: Breath of the Wild. The interesting thing here is that this mod will be exclusive to the CEMU emulated version, so those interested in it will have to game on the PC. Oh, and that the game was not developed with any multi-player mode in mind.
As Fooni noted, this mod will allow 2 people to play locally side by side. In order to achieve something like that, the team will be changing the location of an NPC, and will swap its model to Link. Then it will send all inputs through each game in order to provide a multiplayer experience.
According to Fooni, it will likely take a year or so in order to finish this mod (or have it in a playable state).
Fooni released the first MP images from this mod that can be viewed below.