My side character dream came true when Captain Toad happened.

But others? I'd probably go with Bob Omb. He is always walking forward and you gotta navigate him through puzzles and mazes. Hit the wall 3 times or touch 3 enemies and he explodes.

Some of my choices:

(Although this one has an entire campaign dedicated to him)

Lakitu or The Koopalings.

Oh cool then 

So i want a game with prince plush from epic yarn

Bowser himself, in a game without Mario. He has been co-starring in Super Mario RPG, Super Paper Mario and Bowser's inside Story, but never the sole main character. Even got a game idea about this (short story: strategy game with paper mario looks building up his castle while recruiting the Koopa Troopa and conquering the Kingdom, kind of a prequel to the whole story).

Next, how about turning Captain N: The Game Master into an actual videogame (without it's god-awful renditions of third party characters)? Nintendo nowadays has more than enough worlds to make a huge and diverse Videoland happen. Could be similar to Kingdom Hearts considering it's premise.

Then, The Legend of Zelda featuring Zelda as the actual heroine for a change. And Impa.

Finally, Waluigi really needs a game of his own for once.

Oh, and maybe a game starring the princesses of the Mario Universe (Peach, Daisy and Rosalina) teaming up in a game.

You seriously didn't know?

Well the premise of Captain N: The Game Master is good, but I'm pretty sure they have to change the name. People will keep on thinking of that awful cartoon if they name it that.

I approve of this :)

Link is kidnapped, no one else gives a sh*t.

Its up to Zelda, to save the man she loves.

Princess Peach, because I think she needs to answer some questions about how exactly, she keeps getting kidnapped by the same goddamn group of turtle lizard people. Maybe she should start analyzing her personal choices in life.