(Honestly Reginn would be super fun in Smash, hypothetically. Just riding around in a sword-swinging boar shaped centaur mech that can launch magic missiles.)
That gives me an idea for a fun topic: Rider characters.
"Rider characters" refers to characters who mainly fight while riding a mount, whether it be an animal or a machine (and no, I don't count Wario because he doesn't regularly ride his bike). We got Bowser Jr. in his clown car, so what other rider characters would make great additions to the roster? Here are my ideas.
Animal Riders:
Midna riding Wolf Link
Link riding Epona
A Riekling (from Skyrim) riding a Bristleback boar (also from Skyrim)
A rider character from Fire Emblem (do we have any Lords/protagonists who are normally riders?)
An Intern Shroob riding on a Shroobsworth from Mario & Luigi: Partners in Time (okay, so Shroobsworths aren't animals; they're sentient beings like humans are, as well as fungi)
Kart Mario
A baby Kangaskhan riding her mommy Kangaskhan
Slime Knight from Dragon Quest (though does its Slime mount count as an animal, or is it actually a multi-celled amoeba?)
Machine Riders:
Eggman piloting the Eggwalker (maybe with Big the Cat piloting the Eggwalker as an alternate costume)
Tails being a "transformation" character who can switch between on-foot and piloting the Cyclone from Sonic Adventure 2 (with the latter even transforming into a plane and/or car for certain moves)
Dr. Wily piloting the Wily Capsule
Mechanica from ARMS
Cait Sith from Final Fantasy 7
Orson piloting Toc-Man from Pac-Man World 1 and 3
There's another rider character that I came up with, but since his mount is too big (and his position on his mount can only be done on a mount with that specific size and shape), he'd probably work better as a boss. The rider I'm talking about: Ashnard riding
Rajaion