Super Mario Universe

Super Mario Universe (known as Super Mario Bros. 5: Super Mario Universe in Japan) is a 2020 2D platformer game developed by Nintendo, and Nintendo's first game developed for Steam. It is Nintendo's answer to Sonic Mania, and is heavily inspired by the "classic" Mario games (Super Mario Bros., Super Mario Lost Levels, Super Mario 2, Super Mario 3, Mario World, and Mario Land). There are 4 playable characters: Mario, Luigi, Blue Toad (referred to as just Toad in-game), and Toadette.

Super Mario Universe Plus
This is free DLC for Super Mario Universe released in 2021, similar to Sonic Mania Plus. It adds two new playable characters: Wario and Waluigi.

Trivia

 * The graphics are designed to look like SNES graphics.