The Return to Freddy's
Sugar is a animatronic that was originally present in The Return to Freddy's. However, she was removed due to copyright reasons. The textures for Sugar are still presented in the game's files.
The Return to Freddy's 2
Springtrap is an animatronic that was going to be added in The Return to Freddy's 2, but got removed due to changes in plans. However, a few files for her can be found within the game's file.
Despite her removal, the player can experience an eyeless Springtrap screen very rarely. In one of the minigames, Springtrap was used as a suit by Purple Guy as well.
Here are the only two files for Springtrap in the Custom Night menu screen:
Original Beta Models
Freddy, Bonnie and Chica were originally going to look quite a lot different in the early stages of TRTF 2.
The Return to Freddy's 3
An unused photo of Lockjaw is in the game's data. There appears to be none of Fazbear Fantasy Land's lighting in it.
The Return to Freddy's 4
The Asthma Meter (misspelled as "Asma Meter") is an unused game mechanic for The Return to Freddy's 4. Not much is known about how this works, but it was planned to return in RADSLA, but didn't, as RADSLA was cancelled. Lockjaw was also seen in an image showing him staring into The Office, but it was never seen in the full game.
The Return to Freddy's 5
The Return to Freddy's 5 was formerly known as The Return to Freddy's: Remastered and The Return to Freddy's: Rebooted.
Hybrid Animatronics were Originally the antagonists of The Return to Freddy's 5, while it was called remastered. They were Scrapped and replaced by Torture Animatronics. Their designs were Mangled, Broken down animatronics with parts from others. Here are some images. WIP
Hybrid Toy Animatronics
The Hybrid Toy Animatronics (Toy Freddy, Toy Chica, Toy Bonnie, and Mangle) we're planned but were scrapped early on due to memory limits. Their models have never been shown to the public.
Popper Ping was a torture animatronic, who was cut from the game, due to memory limitations.
Torture Tealer was a torture animatronic, who was cut from the game due to unknown reasons.
Unused Torture Sugar Animatronic Design
Torture Ripdoll was a torture animatronic, who was scrapped from the game. It is unknown why this is, but it's most likely to be the lack of people knowing about him/her.
Co-Op Mode was originally going to a multiplayer mode where you could play with other players in a 8-Bit arena trying to find various objects scattered throughout the map. It was scrapped due to many people trying to impersonate BFP on it and ram limits.
G.P.D Mode (GoldieParaDiner mode) was originally going to be a mode in TRTF 5 that would be like a casual sit and survive FNaF Fangame. Torture Fredbear and Torture Spring Bonnie are the only known antagonists of the mode. It was eventually scrapped by Feline Animations due to ram limits
Adventure Mode was originally going to be a mode in TRTF 5 that was based off of FNaF World. You could play as any of the characters from the TRTF Series including some other fangame characters and joke characters (such as Adventure Gramps, Adventure Lickjuice etc.) Like the other modes it was eventually removed due to ram limits.