In the Mario Kart Wii course "Moonview Highway", billboards can be seen for "The Mushroom Moon", featuring Petey Piranha climbing a building. This may be a reference to the movie poster for the 1933 film "King Kong". In Mario Kart Tour, this poster is updated to replace the 3D renders with 2D artwork, and replaces Petey Piranha with Bowser.

The appearance of Noshis in the R/T version of the Tokyo Blur course is likely a reference to the Japanese film franchise "Godzilla" and its respective genre Kaiju, which feature giant monsters usually depicted attacking major cities.

In the Booster Course pack (as well as the track's appearance in Mario Kart Tour), the advertisement for Barrel Travel in Coconut Mall has barrels which use the exact same sprite as they do in Donkey Kong.

The Koopa Troopa shell bouncing between the pipes of the starting gate to Wii Koopa Cape (a course included in Tour and Deluxe's Booster Course Pass DLC) is a reference to a Koopa Troopa's behavior when Mario/Luigi jump on, kick, or throw a stepped-on shell.

Green Birdo's special skill being the Fire Flower is a possible reference to Super Mario Bros. 2, where Birdos that are green will only shoot fireballs.

The ring seen in the drain portion of Squeaky Clean Sprint resembles the Binding Band from Tostarena in Super Mario Odyssey.

An unused animation of Toadette in her artwork pose can be found in the data. The final version contains only static images for each character.

The racers may have planned to have losing animations for when they reach 5th or lower. In the game's data are Peachette and Pauline's losing voice clips, as well as voice clips from characters that appear in Mario Kart 8 Deluxe (prior to the Booster Course Pass). The final game has the racers appear neutral should the player end up in 5th place or lower.

Since Pauline and Peachette were included as among two of the final four characters in the Booster Course Pass, these unused voice clips may have been a deciding factor behind their inclusion in Mario Kart 8 Deluxe.

Aside from the RMX stages that appear in the original game, Piranha Plant Pipeline is the only Tour stage absent from Mario Kart 8 Deluxe's Booster Course Pass DLC. This was most likely done as a way to avoid confusion with the pre-existing Mario Kart 7 stage Piranha Plant Slide, which contains many similarities to Piranha Plant Pipeline.

Piranha Plant Cove (included in Mario Kart Tour and Mario Kart 8 Deluxe's Booster Course Pass DLC) is the only non-city Tour course that has more than one layout.

Although they remain uncredited, Bandai Namco contributed to the development of Mario Kart 8 Deluxe, Mario Kart Tour, and Arms.

Mario Tennis on the Game Boy Color and Mario Kart Tour are the only Mario multiplayer games where Mario is unlockable. In terms of single-player games, Mario is also unlockable in the single-player mode of Mario Golf on Nintendo 64, as well as Super Mario 64 DS.