Franchise: Super Smash Bros.

Aside from Pikachu and Jigglypuff (whose costume accessories change from game to game), Samus is the only character to have one of her team-based costumes change between games: In the original Smash Bros. and Melee, Samus wears her default (orange) costume when she is on the red team, but in Brawl, her pink costume is used instead. This could be due to the fact that in her Zero Suit, her default costume color is blue. So they needed to give her a new costume that would depict both forms in something closely resembling Red.

Pikachu is the only playable Pokémon in the Super Smash Bros. series to have a visible gender difference in the Pokémon series. Male Pikachus look like the one in Smash Bros, but females have a small indent in their tail, which vaguely looks like a heart. However, gender differences in Pokémon were introduced in Generation IV, which came out after the first Super Smash Bros. and Melee.

Female variants were later included in Super Smash Bros. Ultimate.

Pokémon Trainer is the only character that has a custom name in their original series to not be given a default name in Brawl, and is instead given a generic name. It is clear from the character design that the suitable default name would be "Red" as he is named as such in Pokémon Gold and Silver, and again in the remakes which were released after Brawl. The reason this was done is unknown.

Kirby uses a different dash attack in each of the first three Super Smash Bros. games. In the original Super Smash Bros., he performs a slide tackle. In Melee and Ultimate, he performs "Burning Kirby" (an ability seen in some Kirby games, and merged with the Fire ability in others), while in Brawl and Smash 4, he performs Yo-Yo Kirby's "Break Spin" from Kirby Super Star.

Pikachu is the only character in the entire Super Smash Bros series to only have four costume color options in the first three games.

The following fighters are the only characters in the Smash series to appear in another fighting game:

•Snake appeared in Dream-Mix TV World Fighters as a playable character.
•Mega Man has appeared in the Mega Man Power Battle series, a few Capcom VS games (mainly the Marvel vs. Capcom series) and Street Fighter X Tekken (in his "Bad Box Art" form).
•Donkey Kong also appeared in Punch-Out!! for Wii as a boss.
•Sonic appeared as a playable character in Sonic the Fighters and Sonic Battle.
•Link appeared in the GameCube version of SoulCalibur II.
•Little Mac appears in Punch-Out!!.
•Ryu and Ken are main characters from the Street Fighter series.
•Cloud appears as a playable character in the Dissidia Final Fantasy series.
•Terry is a main character from The King of Fighters series.
•Kazuya is one of the characters in the Tekken series.
•The Kirby series has its own set of spin-off fighting games called Kirby Fighters.
•Charizard, Lucario, Mewtwo and Pikachu appear in the fighting game Pokken Tournament.
•Min Min is one of the characters in ARMS.

In SSB and Melee the first syllable of "Samus" is pronounced /sɑ/ ("saw"). However, in Brawl, it's pronounced /sæ/ ("sah"). This change in pronunciation is consistent with the way Samus is pronounced in Metroid Prime 3: Corruption.

Jigglypuff's eyes are blue in the Pokemon series, but green in the first three games of the Super Smash Bros. series, the same color as a shiny Jigglypuff.

In all of her Smash Bros. appearances, Peach is depicted with a ring on her middle finger, which is absent in other games.

Snake's alternate palette swaps in Super Smash Bros. Brawl and Super Smash Bros. Ultimate are based on wearable camouflage outfits in Metal Gear Solid 3, such as the Fire camo and Spirit camo.

All lines spoken by Marth in Melee/Brawl/Wii U and 3DS are in Japanese. These are what they all are translated:

Marth's taunt - "Everyone, please watch me!" ("みんな、見ていてくれ！")
Marth's counter - "There!" ("そこだ！"), "I won't let you!" ("させるものか！")
Marth's victory poses - "This time, victory is mine, right?" ("今回は僕の勝ちだね。"), "Today, too, I managed to survive." ("今日も生き延びることが出来た。"), "There's no way I can lose!" ("僕は負ける訳には行かないんだ。")

He also has an unused sound file in the Debug Menu of the game which is "Let's Dance!" ("レッツダンス！")

Mario's Cape attack can be used on a taunting character to make them face the other way in ways that are otherwise impossible, like making Wario face the screen while doing his side taunt.

Peach's Final Smash since Super Smash Bros. Brawl is a piece of music from Super Mario Bros 3 that has been sped up. The music is from World 5: The Sky, Coin Heaven bonus levels and in the Warp Zone.

In 2020, after Nintendo sent a cease & desist to the major Super Smash Bros. tournament The Big House for using emulated Slippi netplay in the midst of the COVID-19 pandemic, participants in an official Splatoon 2 tournament collectively changed their tags to include the phrase "#FreeMelee". Shortly after, Nintendo would cancel the tournament, with their statement simply pertaining to "unexpected executional challenges".

In response to this, the Splatoon community hosted their own tournament in tribute to The Big House, titled "The Squid House" - this would end up becoming the biggest Splatoon series tournament to date, attracting 7,000 viewers and raising $28,000 USD, with $3,000 going to charity while the rest went to the participants.