Sure, I'll hop onto this bandwagon with some lukewarm-at-best takes.
1. Super Mario
Mario already has his evil opposite with Wario and a near-clone with Dr Mario.
Luigi got some good buffs in Ultimate to make up for Death in the Simon/Richter reveal so he needs his own dark mirror self to oppose his powerful aura.
That's right! The most requested character with some of the deepest lore and world-shattering power in the Mario universe:
Yup, it's the Green Thunder himself from Super Paper Mario!
...what, were you expecting someone else?
2. Donkey Kong
Sure we could go with Dixie, Lanky or Cranky but in our heart of hearts we all know there's only one pick that makes sense.
Our main monkey, the Kong called Funky!
3. The Legend of Zelda
Honestly, there's a lot of solid characters from the franchise (as Hyrule Warriors helps demonstrate) and while I'd like to take a more obscure pick, it's gotta be Midna, whether that's her imp form, true form or as a duo with Wolf Link.
We have representation of OoT, WW, BotW but no TP (or SS) love with the Link redesign, so...yeah.
Midna's an obvious pick but she's a rare "helper" character that's near universally liked unlike Fi from Skyward Sword, so...
Obvious picks are more antagonists (i.e. Kraid, Mother Brain), the namesake Metroids themselves, the much-despised Adam Malkovich or any of the other bounty hunters from either Prime Hunters on DS or Prime 3 on Wii.
I think maybe Rundas from Prime 3?
Probably the most likeable of the cast from that game and we don't really see much ice powers in smash besides a few moves from the Ice Climbers.
Super-obvious and frequently mentioned, but I don't have strong feelings about the Yoshi sub-series.
Needs a wool-inspired alt skin just like Yoshi.
Rick or Marx are probably the most popular picks I hear about the most?
Will happily push Adeleine from Dream Land 3 and 64's Crystal Shards as an alternative, however
7. Star Fox
Krystal is the obvious pick, with Leon, Peppy or Andross probably the next most obvious?
As much as I'd like to see Krystal promoted from assist despite the fandom's obsession with her, I think Andross is better as a polygon-face assist...
Yeah, gotta be Katt.
She seems to fit the current trio much better than the others would IMO.
Dunno if they'd be a trio that work like Ice Climbers or switch between Jessie, James, Meowth (Wobbufet, etc).
Idea is they'd use traps, weapons, dirty fighting and pokemon-as-single-moves maybe.
I mostly just find the idea of a non-mon Pokemon rep funny and they seem the best fit that's actually widely recognisable and popular across multiple generations.
Promoting Jeff from Assist Trophy was tempting, but with the recent theme of adding villains in...
Well, we can't do eldritch abomination Giygas, so how about Porky, especially as he appeared as a boss in Brawl?
Series actually has a wonderfully underrated cast of oddball characters that never see any development or explanation.
With the series effectively dead, we'll probably never see anyone besides Captain Falcon and maybe Blood Falcon as his Echo Fighter.
Black Shadow is the pick for iconic villain though, especially considering his memetic death by Falcon Punch from the F-Zero anime.
11. Retro Series
There's enough variety of explosives, punches, kicks powerups, animal companions and other stuff from the spinoffs with RPG/adventure elements to make a moveset.
Plus he's already in Smash as an Assist Trophy and fits right in with Mega Man and Pac Man.
queer.af, your cosy queer space queer.af is a mastodon instance for those who are queer or queer-adjacent who would like a more pleasant social media experience.