Banjo-Threeie (lost build of cancelled sequel to platformer game series; early 2000s)
Banjo-Threeie is a cancelled video game that was developed by a British video game developer Rare and was initially going to be published by Nintendo, and later Microsoft Studios (Microsoft Game Studios at the time). The game was going to be the third installment in the Banjo-Kazooie franchise. It was initially developed for the Nintendo GameCube, and later due to Microsoft's purchase of Rare , Xbox and Xbox 360. It is rumored that parts of Banjo-Threeie are present in Banjo-Kazooie: Grunty's Revenge for the Game Boy Advance.
Teaser in Banjo-Tooie
At the end of Banjo-Tooie, Gruntilda Winkybunion (the franchise's antagonist) hints of Banjo-Threeie, telling the player she will be back in that game. 
Spaceworld 2000 Tech Demo
In Spaceworld 2000, a video game event, a few tech demos for the Nintendo GameCube were shown. Games such as Luigi's Mansion, The Legend of Zelda: Twilight Princess and Super Smash Bros. Melee were shown there. A tech demo titled Banjo-Threeie was also shown .
After Microsoft's purchase of Rare, fans have found a code for a build called Banjo X . The code was unbootable, but some character models and text could be found.
In 2006, a trailer for the game was released. in it, Banjo and Kazooie (the franchise's protagonists) found a door, opened it and found a world full of Jiggys, Music Notes and Honey Comb Pieces (the franchise's collectible items). They run around the world, crash into a wall, and the trailer ends.