List of Mario Kart Tour pre-release and unused content
From the Super Mario Wiki
This is a list of pre-release and unused content for Mario Kart Tour.
On April 23, 2019, Nintendo opened applications for participating in a closed beta test of Mario Kart Tour to Android users in North America and Japan, which began on May 22, 2019 and ended on June 4, 2019. The following lists the features included in the beta version of the game. Several of the characters, karts, and gliders listed were not made available in the final game at launch.
Most of the characters retain their special items in the final game; however, Baby Peach, Baby Daisy, Baby Rosalina, and Lemmy's special items are replaced by the Bubble, Morton's special item is replaced by the Giant Banana, Larry's special item is replaced by the Boomerang Flower, King Boo's special item is replaced by the Lucky 7, and Ludwig's and Rosalina's special item is replaced by the Dash Ring. Additionally, in the beta, both Rosalina and King Boo were classified as High-End characters, whereas in the final version, they are classified as Super characters instead.
The beta only featured one tour, named Retro Tour.