It's probably/definitely been made as a thread before, but what new power-up ideas would you add to Mario games? Personally would like to see a classic mushroom in a NSMB game for Mario to have his moveset and physics from the original SMB1
Some power-ups I guess you can take inspiration from the Kirby series. An ability where Mario outright breathes fire would be dandy...hey, why not implement a Bowser Suit as a power-up? You get the abilities of Bowser and you destroy blocks by running into them and breathe fire, but your movement speed is reduced. It does sound OP but maybe it could be some sort of endgame reward.
Mario having a robotic suit would be cool. We've had mostly organic costumes and animals such as frogs. We did have a Propeller Suit but it would be cool to have something more techy.