Let's answer my own question, and try and keep it to only one (or two)
In Smash (Playable)
Bandai Namco - Heihachi/Lloyd
Capcom - Leon Kennedy
Konami - Bill Rizer/Lance Bean
Microsoft - Master Chief/Ori
Nintendo - Dixie Kong
Sega - Gunstar Red or Blue/Beat/Nights
Square Enix - Crono/2B
In Smash (Non-Playable)
Koei Tecmo - Ryu Hayabusa
Ubisoft - Jade/Prince
Not In Smash
Activision Blizzard - Tracer
Aksys Games - Sol Badguy
Bethesda - Doom Slayer
EA - Commander Shepherd
NIS America - Laharl
Paradox - NA
Sony - Kratos
Take Two - Big Daddy
THQ Nordic - War
Warner Bros. - Scorpion
XSEED Games/Marvelous USA - Travis Touchdown
In Smash (Playable)
Bandai Namco - Heihachi/Lloyd
Capcom - Jill Valentine/Viewtiful Joe/Phoenix Wright
Konami - Bomberman/Goemon
Microsoft - Cuphead
Nintendo - Isaac/Dixie Kong
Sega - Tails/Jet Set Radio character?
Square Enix - Sora
In Smash (Non-Playable)
Koei Tecmo - Ryu Hayabusa
Ubisoft - Rayman
Not In Smash
Activision Blizzard - Crash/Spyro
Aksys Games - N/A
Bethesda - N/A
EA - N/A
NIS America - N/A
Paradox - NA
Sony - Ratchet and Clank I guess?
Take Two - N/A
THQ Nordic - N/A
Warner Bros. - N/A
XSEED Games/Marvelous USA - Jack/Pete (Story of Seasons farmer)
I'm gonna add in here Level 5: Layton/Jibanyan
I wrote N/A for anything I have no opinion on or just don't want anything from.
NGL I was gonna talk about how disappointed I was that everyone seems to have glossed over Marvelous (and therefore SoS), but man I just don't care about most of these options. So I don't really have room to talk lmao. It is interesting to me though that it makes this list, most people seem to be aware of Story of Seasons (if only as Harvest Moon), the genre at least appears to be doing well right now in the indie space and with the announcement of multiple new games by Marvelous, and yet no one except for me talks about it at all? People clearly enjoy these games, but I'm starting to suspect that those people and the Smash community just don't intersect much.