Super Mario Maker 2 extra game styles

As revealed in the May 15, 2019 Super Mario Maker 2 Direct, the game's option to switch to the Super Mario 3D World game style was put under an "Extra Game Styles" label.

Because the text was pluralized, fans expected that more new game styles were planned, especially for major post-launch updates, and speculated on which games they would be based on. However, as of the final major Super Mario Maker 2 update in 2020, no game styles have been added beyond the five available at launch.

As another consequence of this situation, it remains unknown what makes a game style count as extra. When switching between other game styles and the Super Mario 3D World option, the course must be reset. Perhaps if a game style added in an update were designed to be more compatible with the original game styles, it would not be sorted under this header. Alternatively, the adjective could just indicate that the 3D World game style is new to Super Mario Maker 2, or even that it isn't seen as part of the core set and could be removed in future Super Mario Maker games. However, as stated, all of this is currently conjecture.

Super Mario Bros. 2
A popular theory for another extra game style was Super Mario Bros. 2. Notably, it is the only original numbered Super Mario Bros. game yet to have a game style in the series, aside from Super Mario Bros.: The Lost Levels which uses the Super Mario Bros. engine. Super Mario Bros. 2 may have garnered additional speculation as an "extra" game style due to featuring different combat mechanics from its contemporary Super Mario games.

The reveal of the SMB2 Mushroom shut down the prospect of Super Mario Bros. 2 having an entire game style in Super Mario Maker 2. The power-up transforms the user into SMB2 Mario, with moves and abilities based on the original game, and is only available in the Super Mario Bros. game style. Aside from being revealed in the final major update's trailer, the course part would make a Super Mario Bros. 2 game style redundant and unlikely to be added.

Imran Khan theorized that a planned Super Mario Bros. 2 theme was folded into the SMB2 Mushroom due to issues adjusting to COVID-19 lockdowns.

"I had definitely heard SMB2 was being developed as a theme, so I am guessing this update is them just throwing everything they're working on out the door and closing it on Mario Maker 2. Kind of hard to blame them with COVID, but yeah."

A Super Mario Land game
Super Mario Land and Super Mario Land 2: 6 Golden Coins were also speculated as extra game styles. If this were the case, the game style would have been the first to be directly based on a handheld game.

Come release, fans viewed the inclusion of the unlockable Superball Flower as a deconfirmation for a game style based on the original Super Mario Land. The Superball Flower is the game's signature power-up, accompanied by the Super Mushroom and Star which were already Super Mario Maker course parts. This is not the case for Super Mario Land 2, whose Carrot was not included but is more in line with the several other signature flight power-ups.

As of the final major update, no game style for a Super Mario Land title was forthcoming.

Another 3D Super Mario game
The inclusion of the Super Mario 3D World game style in a 2D playfield led to hopes that another originally 3D game would be implemented, such as Super Mario 64, Super Mario Galaxy, or fellow Nintendo Switch title Super Mario Odyssey.