Simple. Just say all newcomers you want in future titles. Feel free to get creative and as ridiculous as possible.
Dr. Luigi
Waluigi
Dr. Wario
Dr. Waluigi
Mr. L
Geno
Paper Mario
Paper Luigi
Pauline
Cranky Kong
Funky Kong
Chunky Kong
Dixie Kong
King Bob-Omb
Wart
Impa
Midna
Zant
Tetra
Toon Zelda
Toon Ganondorf
Ganon
Guardian
Darunia
Nabooru
Master Kohga
Skull Kid
The Black Knight
Lyn
Hector
Takumi
Arthur & Arthur
Galacta Knight
Bandana Dee
Trevor Belmont
Dracula
Ms. Game & Watch
Grey Fox
Ocelot
Psycho Mantis
Peppy Hare
Sloppy Toad
James McCloud
Krystal
Ms. Pac-Man
Knuckles
Tails
Eggman
Shadow
Amy
Mega Man X
Zero
Proto Man
Block Man
Gut Man
Sephiroth
Lightning
Medusa
Viridi
Hades
Pandora
Blood Falcon
Samurai Gohro
Jodie Summer
Claus
Starman
Decidueye
Treecko
Lopunny
Gardevoir
Dragonite
Stunfisk (ironically)
Rex
Octoling
Chun-Li
Louie
King Hippo
Banjo-Kazooie
Quote
Misery
Balrog
The Doctor
Curly Brace
Sukapon
Crash Bandicoot
Isaac
Shantae
Dr. Luigi
Waluigi
Dr. Wario
Dr. Waluigi
Mr. L
Geno
Paper Mario
Paper Luigi
Pauline
Cranky Kong
Funky Kong
Chunky Kong
Dixie Kong
King Bob-Omb
Wart
Impa
Midna
Zant
Tetra
Toon Zelda
Toon Ganondorf
Ganon
Guardian
Darunia
Nabooru
Master Kohga
Skull Kid
The Black Knight
Lyn
Hector
Takumi
Arthur & Arthur
Galacta Knight
Bandana Dee
Trevor Belmont
Dracula
Ms. Game & Watch
Grey Fox
Ocelot
Psycho Mantis
Peppy Hare
Sloppy Toad
James McCloud
Krystal
Ms. Pac-Man
Knuckles
Tails
Eggman
Shadow
Amy
Mega Man X
Zero
Proto Man
Block Man
Gut Man
Sephiroth
Lightning
Medusa
Viridi
Hades
Pandora
Blood Falcon
Samurai Gohro
Jodie Summer
Claus
Starman
Decidueye
Treecko
Lopunny
Gardevoir
Dragonite
Stunfisk (ironically)
Rex
Octoling
Chun-Li
Louie
King Hippo
Banjo-Kazooie
Quote
Misery
Balrog
The Doctor
Curly Brace
Sukapon
Crash Bandicoot
Isaac
Shantae