I've got it! A Bowser's minion fighting game!

Call of Mushroom: Boo's

he was the antagonist of that Mario DDR game for what that's worth lol.

Bowser Godzilla game where you just run around a sandbox city and wreck shit while fighting Kaiju :P

Play the Bowser segments in Paper Mario: Thousand Year Door and tell me a Bowser game wouldn't be the funniest damn thing you've ever played.

Actually...Wario's Woods was exactly that, I forgot about that. It was where Toad had to save some woods in a remote area of the Mushroom Kingdom from Wario. It had multiplayer and everything. For some reason there's no sales data on it though. My sisters were playing it together on 3DS virtual console the other day. It was kind of like Dr. Mario, except instead of a pill bottle it's the inside of a tree, and instead of viruses and pills it's monsters and bombs, and toad can pick up the monsters and bombs. Some can only be killed horizontally, vertically, or diagonally, and some have two hit points and change color when damaged.

So I guess Toad has been the star of a game, sort of, he just wasn't the title character.

Nintendo should release DLC for Super Mario 3D World where you play as Bowser going on his journey to capture the pixies.

There are seven pixies, so have seven worlds, it's DLC so they don't have to be huge maybe four levels in each. At the end of each world Bowser captures one of the pixies. After completing the seventh world the green pixie flees through a clear pipe and Bowser follows, the DLC ends there, as the cutscene leads into the beginning of Super Mario 3D World.

Only for part of it. Wario was the antagonist after that, and then Bowser was the final boss. It is the biggest part Waluigi has ever played in a game though. Poor bastard. Maybe 2020 will be the year of Waluigi and he'll get his own game to celebrate, lol.

 A spin-off where Peach works as an expensive prostitute. The Deviantart community would rejoice!

Ahem...there's uh...this fan made flash game...she fucks Goombas and Morton Koopa...if that counts...I don't think I can post a link here...