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.
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.
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.
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.
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.
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.
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.
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 Speed Highway, several billboards can be found depicting an unknown female character. In 2020, Satoshi Okano, a former designer at Sega who worked on Sonic Adventure, revealed that this was a scrapped spider character he designed with the prototype name "Spider Girl", and posted an old sketch of the character alongside a sketch of another scrapped character, a bat named "Fly the Vampire". In 2023, Okano posted an inked version of the original Spider Girl sketch from the same time period alongside several inked sketches from the development of Samba de Amigo. Spider Girl's appearance on the billboards in Sonic Adventure suggests that the character lasted far enough into the game's development to receive a 3D model, but the character was ultimately scrapped for unknown reasons, and this 3D model has yet to surface on its own. It's unknown what role either Spider Girl or Fly were intended to have, though fans have noted that Spider Girl has some similarities to Rouge the Bat from Sonic Adventure 2, namely that both characters have large bosoms and prominent heart-based/romantic imagery.
Disney's Animated Storybook: Toy Story and Toy Story Activity Center were developed by a devision of Pixar known as the Interactive Products Group, which exclusively made video game content. The division was closed down when the Toy Story 2 movie entered production, and merged into Pixar's main movie animation staff, as the animators behind the first film were working on A Bug's Life and the IPG had already proved itself by making as many frames of animation for their games as there was in the first Toy Story, with a near-identical quality. Due to the shuttering of the IPG, later Pixar PC games using pre-rendered graphics, such as A Bug's Life Activity Center and Monsters, Inc. Scream Team Training, would have significantly lower quality animation than the movies, and Toy Story would be the only Pixar film to have an Animated Storybook based on it.
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
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.
The texture for Goro Majima’s jacket in Yakuza 3 is of noticeably poorer quality from his appearence in other games. This has even lead to a mod being made which replaces his jacket in Yakuza 3 Remastered for PC with a model more close to his jacket in Yakuza 4 Remastered.
There is an unused model of the Statue of David by Michelangelo in Squidward's prop set. This was likely intended for his air down strong, where he slams down with a block of marble, referencing the SpongeBob episode "Artist Unknown", where SpongeBob makes the same statue by accident. The model has a clam on its groin as censorship, just like in the original episode, but does not have the nose Squidward places on it.
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!"
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.
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.
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.
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.
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.
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.
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. 
The Utah Teapot, a 3D graphics in-joke, can be found in the data of Watch Dogs 2 as an unused vehicle.
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.
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.
In the files of Chicken Run, there is an unused model for Edwina, a character who dies and gets eaten early into the movie.
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 Speed Highway, several billboards can be found depicting an unknown female character. In 2020, Satoshi Okano, a former designer at Sega who worked on Sonic Adventure, revealed that this was a scrapped spider character he designed with the prototype name "Spider Girl", and posted an old sketch of the character alongside a sketch of another scrapped character, a bat named "Fly the Vampire". In 2023, Okano posted an inked version of the original Spider Girl sketch from the same time period alongside several inked sketches from the development of Samba de Amigo. Spider Girl's appearance on the billboards in Sonic Adventure suggests that the character lasted far enough into the game's development to receive a 3D model, but the character was ultimately scrapped for unknown reasons, and this 3D model has yet to surface on its own. It's unknown what role either Spider Girl or Fly were intended to have, though fans have noted that Spider Girl has some similarities to Rouge the Bat from Sonic Adventure 2, namely that both characters have large bosoms and prominent heart-based/romantic imagery.
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.
The texture for Goro Majima’s jacket in Yakuza 3 is of noticeably poorer quality from his appearence in other games. This has even lead to a mod being made which replaces his jacket in Yakuza 3 Remastered for PC with a model more close to his jacket in Yakuza 4 Remastered.
There is an unused model of the Statue of David by Michelangelo in Squidward's prop set. This was likely intended for his air down strong, where he slams down with a block of marble, referencing the SpongeBob episode "Artist Unknown", where SpongeBob makes the same statue by accident. The model has a clam on its groin as censorship, just like in the original episode, but does not have the nose Squidward places on it.
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. 
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.
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.
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.