Both Mach Rider's identity and gender are ambiguous. They are portrayed with a muscular build, and the NES and Famicom versions' manuals never use any gendered pronouns to refer to them. The arcade port Vs. Mach Rider's stage clear screens slowly introduce piece-by-piece an image of a skimpily-dressed woman (bearing similarities to Jane Fonda's appearance in the 1968 film Barbarella) holding a dagger, but it is never specified if this character is Mach Rider, or one of the other wasteland survivors. However, Mach Rider's trophy description in Super Smash Bros. Melee years later lists them as a male character with he/him pronouns. Even later on, Captain Rainbow, a game centered around obscure and neglected Nintendo heroes, has an unused model for Mach Rider that, while not having visible breasts due to wearing armor, portrays them with a feminine skinny waist.
The skin Dark Star Cho'Gath was made in collaboration with a critically ill League of Legends player named Bryan, who met Riot Games through a partnership with the non-profit charity the Make-A-Wish Foundation. Bryan wished to "meet the creators of Riot Games, and make a skin with them." Dark Star Cho'Gath was chosen between three skin designs and inspired by Bryan's love of outer space. The skin's theme music is based on a clarinet performance from Bryan. All profits collected from the skin until July 20, 2018 were donated to various non-profit organizations around the world.
In the ending cutscene of New Super Mario Bros. 2, the Koopalings carry Bowser by the tail after his defeat while Mario and Peach run home. Due to the strain that rendering a large character like Bowser alongside the models of 9 other characters and a vehicle could cause on the 3DS hardware, Bowser does not use his regular model used in the rest of the game, but rather a set of flat pre-rendered graphics tilted to appear 3D.
Nickelodeon All-Star Brawl's files have a set of unused placeholder models, all in a significantly more realistic style than the game and not based on any Nickelodeon IPs, comprised of a female pirate model from Adobe's Mixamo service; pirate, military, and ninja-themed props and weapons with unknown sources; and a "dangerous pumpkin" taken from a Unity asset store pack, which also has a leftover UI graphic alongside multiple other asset store props.
Jellyfish Fields, Harmonic Convergence, and Duck, Duck, Pie! all have unused early level geometry. These are all loaded in when the final stages are played and are simply hidden from view. Harmonic Convergence is very close to its final form; Jellyfish Fields lacks textures, but it can be seen that it has the sign on the base platform instead of the background; Duck, Duck, Pie! was originally a completely different style of pie that has its filling visible, which was likely changed to prevent depth perception issues.
In a rough time span from 1987 to 1988, a commercial for the Nintendo Entertainment System - often colloquially referred to as either "Scary Nintendo Commercial" or "We Are Nintendo, You Cannot Beat Us" - was aired on Australian television by Mattel, the region's Nintendo distributor at the time. The commercial featured primitive CGI renditions of antagonists from different NES games (Smick from Gyromite, Bowser and Lakitu from Super Mario Bros., and the laughing scent hound from Duck Hunt, lead by an original character resembling Max Headroom, a dystopian TV character who was being used to market Coca-Cola at the time) mocking the viewer with the phrase "you cannot beat us", set to the ominous castle music from Super Mario Bros.
This commercial has sustained a decent viral popularity, often being featured on listicles and review videos related to bizarre 1980s or Nintendo commercials, but it is not as well known that the advert was part of a larger Nintendo campaign, and that "you cannot beat us" is a variation on another, more frequently-used Nintendo slogan from the country - "it can't be beaten!" This phrase was used in a series of significantly less frightening live-action commercials showing children playing the games while doing imitations of the voice from the CGI commercial, winning, shouting "Beat 'cha!", and then having a hazard from the game enter their room (a tennis ball while playing Tennis, a martial artist while playing Kung Fu, and a generic effect where their chair blasts into the sky for Super Mario Bros.) while a filtered voice announces "We are Nintendo, we do not like losing!"
The first-ever footage of Luigi as a playable character in Super Mario 64 was discovered through an old VHS tape in 2023. The footage was captured by a Japanese broadcaster recording footage of Nintendo's 1995 Space World trade show in Japan for a TV program covering the event. Despite this, the footage of Luigi is not actually the primary focus of the clip and as such can barely be seen at all. The video shows Luigi falling back down after performing a spin-jump in what appears to be a red and white test area.
Originally, going by some of the initial concept art as well as early gameplay footage for Star Fox Adventures, the tip of Krystal's staff was meant to transform whenever Fox performed one of its magic abilities. For example, when Fox performed the Ground Quake ability, it'd transform into a hammer. Curiously, one of the pieces of concept art mentions the staff transforming into a wing tip to give Fox the ability to glide, which goes unused in the final game. The models for these staff transformations were also found within the E3 2002 kiosk version of Star Fox Adventures. Ultimately, this went unused in the final game.
SFA Space World 2001 trailer showing Krystal's staff tip transforming into a hammer when Fox performs the Ground Quake ability: https://youtu.be/OliAnoALccg?t=15
Hugh has an unused model of a spear, referencing the popular caribou hunting chant scene from The Adventures of Jimmy Neutron: Boy Genius episode "Jimmy on Ice". While it is fully textured and loaded into the game whenever Hugh is, it is not used.
About a month before the release of Yakuza: Like a Dragon in North America, the protagonist of that game, Ichiban Kasuga, made his playable debut in the region in the game Streets of Kamurocho, a reskin of a Streets of Rage 2 level with Yakuza characters and locations. His moveset is a reskin of Axel Stone from that game as are the other two playable characters: Kazuma Kiryu and Goro Majima.
In Crash Bandicoot 4: It's About Time, the relics only appear as 2D images. However, complete 3D models can be found for all of them inside the game, including three variants of the N. Sanely Perfect relic that seem to be tiered (one being a skull, another being a skull with crossbones, and the last being a skull with crossbones; wings; horns; and a more menacing face which is closer to the final N. Sanely Perfect Relic aside from the wings), all with their own animations.
Ed, Edd n Eddy: Scam of the Century uniquely uses flat character heads on 3D bodies. However, Ed's texture contains segments from a 3D head, suggesting that the game may have originally used fully 3D characters.
Early footage of Dinosaur Planet shows that Sabre and Krystal were to utilize the Projectile spell by firing it directly from their hands. It seems this was already scrapped by the time of the December 2000 build that was leaked on the internet in early 2021, as Sabre (or Fox McCloud, who has already replaced Sabre at this point) and Krystal instead fire projectiles through their sword and staff respectively. This would carry over into Star Fox Adventures, where Fox can fire magic projectiles through Krystal's staff.
One holdover from this early idea that remains in both the December 2000 build of Dinosaur Planet and the final Star Fox Adventures is within the prologue, where Krystal, riding on top of a CloudRunner, is inexplicably shown to be able to fire blasts of magic from her own hands in the battle against General Scales' galleon.
Unused models of both Sabre and Krystal's arms can be found within the files of the leaked Dinosaur Planet ROM.
Inside the files of Wii Fit is an early model for the trainer who less resembles a mannequin and moreso appears to be distinctly white with blonde hair and almost fully realistic. The exceptions to this being her feet which have no toes, and her clothes that - while roughly the same color as the final character - are textureless (note that the attached image appears to be wearing a white onesie due to a rendering error). Based on the structure of the model and the full version of her body texture, it is apparent that the model was originally nude and the developers simply retextured parts of her body to create her clothing. The clothing meshes have their UV data removed, making them unable to use the body texture. The trainer also has a few unused animations of some warm-up stretches and yoga poses, but her shoulders get distorted and inverted due to how they are rigged. Additionally, while the warm-up poses flow together, the yoga poses (different steps of the Tree pose) are almost completely still and have no transition between them.
The European box art for Sonic 3D: Flickies' Island was not a CGI image, but rather a clay model created by Me Company, a Japanese clay studio whose in-house style involved digitizing its models and editing in elements to make them appear computer-generated.
At some point in the 2000s, a promo video was made by THQ and Toys R Us to encourage Toys R Us store owners to stock THQ video games. This tape opens with a strange, off-model rendition of SpongeBob not resembling any of his video game models and with notable details such as his pore locations, finger shape, and amount of fingers being completely off from Nickelodeon's style guide. The video also has imitation music not taken from either the SpongeBob SquarePants TV show nor any of its video games. Despite this, the video does use legitimate background art from the cartoon, and has voice work seemingly done by SpongeBob's voice actor Tom Kenny. While SpongeBob's model seems to be original, Patrick's model is taken from Nicktoons Unite!, sporting the distinctive face-long mouth and half-shut eyelids of his model used throughout the Nicktoons platformer game series. The complete promo video is not known to have been preserved.
Some of the characters during Star Fox Assault's briefing cutscenes feature details in the back that are typically unseen by the player, since the models are normally only viewed from the front. The only way around this is to move the camera using an emulator.
One such example is Beltino Toad, Slippy Toad's father. Rotating his model around reveals his coat has the logo for Space Dynamics, the manufacturer for many of the Star Fox team's vehicles, such as the Arwing, Great Fox and Landmaster.
This particular logo had actually first appeared in the official Star Fox Mission File Printout guidebook released for the original Star Fox on SNES in Japan, back in 1993.
Both Mach Rider's identity and gender are ambiguous. They are portrayed with a muscular build, and the NES and Famicom versions' manuals never use any gendered pronouns to refer to them. The arcade port Vs. Mach Rider's stage clear screens slowly introduce piece-by-piece an image of a skimpily-dressed woman (bearing similarities to Jane Fonda's appearance in the 1968 film Barbarella) holding a dagger, but it is never specified if this character is Mach Rider, or one of the other wasteland survivors. However, Mach Rider's trophy description in Super Smash Bros. Melee years later lists them as a male character with he/him pronouns. Even later on, Captain Rainbow, a game centered around obscure and neglected Nintendo heroes, has an unused model for Mach Rider that, while not having visible breasts due to wearing armor, portrays them with a feminine skinny waist.
In the Wii and PS2 versions of SpongeBob's Atlantis SquarePantis, SpongeBob's model has two brains hidden in his body, one behind each eye.
The skin Dark Star Cho'Gath was made in collaboration with a critically ill League of Legends player named Bryan, who met Riot Games through a partnership with the non-profit charity the Make-A-Wish Foundation. Bryan wished to "meet the creators of Riot Games, and make a skin with them." Dark Star Cho'Gath was chosen between three skin designs and inspired by Bryan's love of outer space. The skin's theme music is based on a clarinet performance from Bryan. All profits collected from the skin until July 20, 2018 were donated to various non-profit organizations around the world.
In the ending cutscene of New Super Mario Bros. 2, the Koopalings carry Bowser by the tail after his defeat while Mario and Peach run home. Due to the strain that rendering a large character like Bowser alongside the models of 9 other characters and a vehicle could cause on the 3DS hardware, Bowser does not use his regular model used in the rest of the game, but rather a set of flat pre-rendered graphics tilted to appear 3D.
Nickelodeon All-Star Brawl's files have a set of unused placeholder models, all in a significantly more realistic style than the game and not based on any Nickelodeon IPs, comprised of a female pirate model from Adobe's Mixamo service; pirate, military, and ninja-themed props and weapons with unknown sources; and a "dangerous pumpkin" taken from a Unity asset store pack, which also has a leftover UI graphic alongside multiple other asset store props.
Jellyfish Fields, Harmonic Convergence, and Duck, Duck, Pie! all have unused early level geometry. These are all loaded in when the final stages are played and are simply hidden from view. Harmonic Convergence is very close to its final form; Jellyfish Fields lacks textures, but it can be seen that it has the sign on the base platform instead of the background; Duck, Duck, Pie! was originally a completely different style of pie that has its filling visible, which was likely changed to prevent depth perception issues.
In a rough time span from 1987 to 1988, a commercial for the Nintendo Entertainment System - often colloquially referred to as either "Scary Nintendo Commercial" or "We Are Nintendo, You Cannot Beat Us" - was aired on Australian television by Mattel, the region's Nintendo distributor at the time. The commercial featured primitive CGI renditions of antagonists from different NES games (Smick from Gyromite, Bowser and Lakitu from Super Mario Bros., and the laughing scent hound from Duck Hunt, lead by an original character resembling Max Headroom, a dystopian TV character who was being used to market Coca-Cola at the time) mocking the viewer with the phrase "you cannot beat us", set to the ominous castle music from Super Mario Bros. 
Originally, going by some of the initial concept art as well as early gameplay footage for Star Fox Adventures, the tip of Krystal's staff was meant to transform whenever Fox performed one of its magic abilities. For example, when Fox performed the Ground Quake ability, it'd transform into a hammer. Curiously, one of the pieces of concept art mentions the staff transforming into a wing tip to give Fox the ability to glide, which goes unused in the final game. The models for these staff transformations were also found within the E3 2002 kiosk version of Star Fox Adventures. Ultimately, this went unused in the final game.
Hugh has an unused model of a spear, referencing the popular caribou hunting chant scene from The Adventures of Jimmy Neutron: Boy Genius episode "Jimmy on Ice". While it is fully textured and loaded into the game whenever Hugh is, it is not used.
In the files of Chicken Run, there is an unused model for Edwina, a character who dies and gets eaten early into the movie.
In Crash Bandicoot 4: It's About Time, the relics only appear as 2D images. However, complete 3D models can be found for all of them inside the game, including three variants of the N. Sanely Perfect relic that seem to be tiered (one being a skull, another being a skull with crossbones, and the last being a skull with crossbones; wings; horns; and a more menacing face which is closer to the final N. Sanely Perfect Relic aside from the wings), all with their own animations.
Ed, Edd n Eddy: Scam of the Century uniquely uses flat character heads on 3D bodies. However, Ed's texture contains segments from a 3D head, suggesting that the game may have originally used fully 3D characters.
The Utah Teapot, a 3D graphics in-joke, can be found in the data of Watch Dogs 2 as an unused vehicle.
Early footage of Dinosaur Planet shows that Sabre and Krystal were to utilize the Projectile spell by firing it directly from their hands. It seems this was already scrapped by the time of the December 2000 build that was leaked on the internet in early 2021, as Sabre (or Fox McCloud, who has already replaced Sabre at this point) and Krystal instead fire projectiles through their sword and staff respectively. This would carry over into Star Fox Adventures, where Fox can fire magic projectiles through Krystal's staff. 
Inside the files of Wii Fit is an early model for the trainer who less resembles a mannequin and moreso appears to be distinctly white with blonde hair and almost fully realistic. The exceptions to this being her feet which have no toes, and her clothes that - while roughly the same color as the final character - are textureless (note that the attached image appears to be wearing a white onesie due to a rendering error). Based on the structure of the model and the full version of her body texture, it is apparent that the model was originally nude and the developers simply retextured parts of her body to create her clothing. The clothing meshes have their UV data removed, making them unable to use the body texture. The trainer also has a few unused animations of some warm-up stretches and yoga poses, but her shoulders get distorted and inverted due to how they are rigged. Additionally, while the warm-up poses flow together, the yoga poses (different steps of the Tree pose) are almost completely still and have no transition between them.
The European box art for Sonic 3D: Flickies' Island was not a CGI image, but rather a clay model created by Me Company, a Japanese clay studio whose in-house style involved digitizing its models and editing in elements to make them appear computer-generated.
At some point in the 2000s, a promo video was made by THQ and Toys R Us to encourage Toys R Us store owners to stock THQ video games. This tape opens with a strange, off-model rendition of SpongeBob not resembling any of his video game models and with notable details such as his pore locations, finger shape, and amount of fingers being completely off from Nickelodeon's style guide. The video also has imitation music not taken from either the SpongeBob SquarePants TV show nor any of its video games. Despite this, the video does use legitimate background art from the cartoon, and has voice work seemingly done by SpongeBob's voice actor Tom Kenny. While SpongeBob's model seems to be original, Patrick's model is taken from Nicktoons Unite!, sporting the distinctive face-long mouth and half-shut eyelids of his model used throughout the Nicktoons platformer game series. The complete promo video is not known to have been preserved.
Some of the characters during Star Fox Assault's briefing cutscenes feature details in the back that are typically unseen by the player, since the models are normally only viewed from the front. The only way around this is to move the camera using an emulator.