Chrom's Black costume
While there is little difference to default Chrom, I think the black costume is based on his portrait in-game, concept art and even his overworld sprite in Fire Emblem Awakening. DoctaShield (talk) 16:09, September 19, 2021 (EDT)
Samus's Green alts
It could be posible that Zero Suit Samus white and green alts are based on the monochromatic and original screen color of the Game Boy in her appearance in Metroid II: Return of Samus. That could also add a little to the normal Samus green alt. On the other hand adding Dark Samus (who is the reincarnated form of Metroid Prime, a mutated Metroid) to the mix, Metroids are primarily of color green with red parts (like Samus green costume) and even some have blue parts (example Queen Metroid) just like in Dark Samus's costume. DoctaShield (talk) 02:54, October 19, 2021 (EDT)
Ike Purple alt
I think his costume is lightly based on Micaiah from Fire Emblem: Radiant Dawn, mostly because both have a shirt of color purple with small stripes of pink. I can barely see it right, but the color of the bandana Ike uses is a shade of blue just like Micaiah's scarf and hair ornament. The only thing that is weird is the boots where Ike's are red with some light brown strings hanging out while Micaiah is light brown boots with red strings. For this I consider her important because she is the protagonist of this game as well as Ike is. DoctaShield (talk) 03:43, October 19, 2021 (EDT)
Sora's P7 Costume
Unlike his P6 Costume which is nearly, if not entirely, 1-to-1 with his Valor Form from KH2, Sora's P7 Costume is actually a cross between Wisdom Form and his KH3D outfit, using the KH3D outfit as the base with Wisdom Form's color scheme and flame marks. So basically, it's what Wisdom Form would have looked like if KH2's Drive Forms were in KH3D. 192.208.172.127 07:04, October 19, 2021 (EDT)
Ice Climbers
Considering the limits of what the original game offers, I got some ideas from where some colors might be based on. One thing that the game offers you with a variety of colors are vegetables. This are for futher reference: the sprites and the Brawl Trophy.
Green: Based on Cucumber (or Cabbage but i feel cucumber have a more darker shade of green) and Corn. The combination could also reflect the lower heighs of the mountain in the game being of the color green and a light orange with yellow.
Brown: Based on Mushroom and Potato, if we consider potatoes having a more gray-ish shade than a brown but could also represent Topi, an enemy from the international release of the game considering the white/light gray color of the furr and the yellow arms and feets just like the boots and mittens of both of them.
Orange: Based on the Pumpkin (or Carrots) and Eggplant, this combination could also reflect the levels where the Eggplant appears being hold by the Condor who is orange. Also some levels in the Arcade version of the game, in some heighs change to purple and a dark orange.
Blue & indigo: This could reference the different shades of blue used for anything ice related in the sprite work as well as the Title screen logo and Popo's results screen. For INDIGO, Popo resembles colors in the sprite of the Eggplant which used dark blue and purple just like the parka and mittens respectively. DoctaShield (talk) 00:29, October 20, 2021 (EDT)
Marth Red costume
I was serching for ideas of why even though Marth RED costume have a black shirt instead of a red one. I searched on who or what could reference within his games outside of Enemy Units. A character who also is in the status of royalty just like Marth is Minerva. While most of her old apparences feature her in mostly red with some legwear in black or dark red to brown, in Mystery of the Emblem you can see she is totally red and darker red on some parts while in the Trading Card Game and Shadow Dragon looks a bit more brown so the only thing that she does not have is black shirt, but in the book Fire Emblem The Complete, a piece of artwork shows this desing featuring a the black shirt, yellow to orange details and even have a red cape even tho the green stone ornament is still red for Marth. Some purple details can be seen in Marth (boots straps and the other side of the cape) probably evoking a bit of Minerva's (cape?) in the past two references but also her design in Shadow Dragon and the Blade of Light in which she was wearing completely purple. I believe this could be the reference all along since Melee because the book cameout in 1996 and the TCG is probably that old too since it only covered games of the SNES era. DoctaShield (talk) 20:22, October 20, 2021 (EDT)
Star Fox in general
All the Orange alts: Artwork of Fox and Falco in Star Fox. This also includes Wolf being based on Fox.
Fox
White: Might resemble Bill in Star Fox 64 and Star Fox 64 3D and the Cornerian Fighter.
Yellow: Also resembles Slippy in Star Fox Assault and Star Fox Command.
Falco
Green: Resembles Falco in Star Fox Adventures.
Blue: Resembles the colors of the Arwing, Slippy in Star Fox (most games minus Assault and Command) and recently Fay in Star Fox 2.
Pink: Resembles Katt color scheme in Star Fox 64, Star Fox Zero and some cutscenes in Star Fox Command.
- PD: HERE a link for a picture of Starlink Wolf from their wiki if needed. Edit: Forgot to sign in the first place DoctaShield (talk) 01:04, October 21, 2021 (EDT)
Dr. Mario's Purple costume
His Purple color possibly takes inspiration of the Purple Checkboard background in the original Dr. Mario game on the NES, due his coat is purple and gloves are almost black. —Preceding unsigned comment added by 70.93.60.77 (talk • contribs) 19:56, October 21, 2021 (EDT)
Also, his necktie is orange, matching with the display window in-game. —Preceding unsigned comment added by 70.93.60.77 (talk • contribs) 17:41, October 25, 2021 (EDT)
Ganondorf (some ideas)
Violet: Might represent Gerudo Guards in Ocarina of Time and Majora's Mask. Choose this because this alt still have red in the outfit as the Gerudo's outfit does.
Green: Might represent Gerudo Warriors in Ocarina of Time as a texture glitch matches Link's tunic even tho in Majora's Mask Gerudo Pirates are also found in light green with no glitch linked to it. Ganondorf have a Koholint armor that matches more this alt in Hyrule Warriors Legends. Easily could reference Farore, the goddess of Courage and whom Link's triforce is well... linked.
Purple: Because of the clothes being purple as a whole, it might represent Din as she appears in Ocarina of Time. She is the goddess of Power, the same part of the triforce that Ganondorf got in that game. Yuga Ganon might also work as his Lorule armor in Hyrule Warriors Legends is purple. Yuga himself also mostly wears Purple.
Brown: as extra, brown is also the color of Ganon in The Legend of Zelda when gets weakened. The sprite is here. DoctaShield (talk) 02:39, October 22, 2021 (EDT)
Captain Falcon
The black costume also appeared later on in as an alt in F-Zero GX/AX as an alternate color for him. DoctaShield (talk) 20:44, October 22, 2021 (EDT)
Kid Icarus series
Pit
Yellow - Based on the Centurions artwork from the Instruction Booklet of Kid Icarus where they are depicted mostly yellow albeit named "Centurian" in the manual and in Japan they are named "Icarus".
Blue - Also resembles some artworks in Instruction Booklet of Kid Icarus.
White - Could be a reference to Centurion Strongarm that have white boots and golden helmet (interpreted as the hair?).
Dark Pit
Green - Might resemble Thanatos green color scheme in Kid Icarus.
Yellow - Same as Pit.
Red - Resembles Twinbellows in Uprising being dark red and yellow flames with the back bones being white just as Dark Pit's wings.
Blue - Might also resemble Pandora, as she was the one who created him (in a way) and using her power to fly later on.
Palutena
Blue - Resembles herself in the Instruction Booklet of Kid Icarus. Also resembles Pandora.
BTW, I linked to an official pdf of the KI instruction booklet by Nintendo so I don't know if the link will work or is right to be referenced here. DoctaShield (talk) 01:26, October 26, 2021 (EDT)
Bowser's P5 (Grey) Costume
Isn't there the possibility that it's been inspired by Shigeru Miyamoto's original artwork for Super Mario Bros.? Kusanagi (talk) 14:43, October 27, 2021 (EDT)
- Well, it cannot be because the Super Mario Bros. artwork was previously referenced in Brawl as a the Blue skin along side the grey one. Bowser's Alternate Costumes in Brawl DoctaShield (talk) 01:32, October 30, 2021 (EDT)
Colors for some
Bowser: "Orange" also matches up with artwork of him between the NES and SNES era (Super Mario Bros.: The Lost Levels, Super Mario World) and the N64 era (Super Mario 64) but the hair is totally Ultimate version of Giga Bowser.
Cloud: "Advent Blue" also resembles Cloud's artwork in some boxarts of the Final Fantasy VII: Advent Children movie.
Corrin: "Orange" is based on Oboro, Takumi's retainer from Fate.
Daisy: "Red" could reference Peach's sprite on the Virtual Boy game Mario's Tennis, the first tennis-related Mario game. "Black" could reference Daisy's sprite in Super Mario Land with even a bit of green of the Game Boy screen.
Diddy Kong: "Green" furr resembles the yellow alt in DK: King of Swing; "Blue" vest is also available in Donkey Kong 64 Multiplayer and DK: King of Swing; "Yellow" cap also resembles the source of "White" but the furr is closer to the monochrome appearance in Donkey Kong Land or the blue alt in DK: King of Swing.
Donkey Kong: "Black" fur could also reference the sprites of the GB's Donkey Kong Land and GBC's Game & Watch Gallery 2. "Green" also resembles his sprite in Donkey Kong for the Game Boy albeit being a darker green.
Greninja: "Red" is Crawdaunt; "Pink" is Lickitung and/or Lickilicky; "Green" is Politoed and/or Kecleon.
Isabelle: "Pink" resembles Pelly while "Purple" resembles Phyllis, sisters that also worked at the Town Hall in games like Wild World and City Folk.
King Dedede: "Purple" also resembles Masked Dedede in Triple Deluxe that was controlled by Queen Sectonia which also his obi have patterns based on her.
Luigi: "Cyan" and "Yellow" are also part of the sprite rotation in the Invincibility effect in Super Mario Bros.. "Blue" is also available in the multiplayer ScareScraper of Luigi's Mansion: Dark Moon. "Yellow" is also available in Mario Golf and Mario Tennis on the N64 albeit the colors are inverted.
Mr. Game & Watch: "Green" also the Game Boy but the dark pixels i guess.
Peach: "Yellow" dress could still be based on the classic appearance of Daisy, or Peach's sprite on the GBC sports games of Mario Tennis, Mario Golf and Mobile Golf. I have seen some say its the Golden Drink effect from Super Mario Party that cover the player completely in gold.
Pyra/Mythra: "Saturated" Pyra resembles the Shulk's Monado while Mythra might slightly resemble Nia's blade form; "Metal" might be taken from Rex's interpretation of Pneuma (Pyra + Mythra) as "Coffee with Milk" (Brown and White), Pyra resembles the Zohar from Xenosaga while Mythra might resemble the Mini-Zohar which is small white version of it.
Robin: "Blue" resembles the male avatar from Fire Emblem: New Mystery of the Emblem named Kris, maybe the purple parts were taken from the female avatar.
Sonic: "Purple" might also resemble Blaze the Cat as she was also playable in her debut game Sonic Rush.
I ignored some because I have commented them before but others I might have already but I was not so "straight to the point", or the previous games already have it. DoctaShield (talk) 01:05, November 11, 2021 (EST)
Daisy's pink costume
I'm pretty sure Daisy's pink costume is inspired by her Super Mario Bros Print World art (https://www.mariowiki.com/File:SMBPW_Princess_Daisy.png) given the color scheme is nearly identical, more so than Peach's early artworks and sprites. ANTI (talk) 20:19, November 19, 2021 (EST)
Yellow Pit and Red Dark Pit
I might be stretching things way too much with these, but I think I made a major discovery. Dark Pit's red costume looks like Twinbellows, down to the lighter wings representing the exposed spine. Also, Pit's yellow costume looks almost exactly like his design in the official Captain N comic book.The Other Jared (talk) 20:23, December 3, 2021 (EST)
- I hope they read yours, I said the same thing about Red Dark Pit like a month ago XD. IMO yellow Pit might reference the centurions. DoctaShield (talk) 14:51, December 6, 2021 (EST)
Luigi's cyan costume
I'm pretty sure this resembles Luigi's in-game appearance in Mario & Luigi: Bowser's Inside Story. —Preceding unsigned comment added by TomAndTheCats (talk • contribs) 20:46, December 15, 2021 (EST)
- That game released after Brawl which introduced the alt because Brawl released in 2008 and the Mario game you listed released in 2009.
Thegameandwatch 
The Nerd 03:11, December 16, 2021 (EST)
- Dang, if only Sakurai had had a heart and changed the color of the emblem on his cap...
Richter's Harmony of Despair color palette
I'm kinda hesitant to point this out because I know that every references need a source link to further enforce the truth yet unfortunately I only have a video of said color palette about guides to use unused color palette in the game as there's seems to be no sprite rip (https://youtu.be/xtFxXNojBno?t=15). As you can see in the timestamp while blurry it is still kinda noticeable that there are some similarity with some of his costume, specifically the black, red, green, purple, and white and I think this reference is acceptable as HoD came out years before Ultimate.
If there's someone out there who is a series expert I humbly need a further examination. Command Stratos (talk) 07:09, January 5, 2022 (EST)