The subtitle has a reason to exist. Some are harder to pinpoint, honestly. Let's start with the more straightforward additions and move to the more obscure ones from there:
The in-game missing animatronics

Shadow Rat

Shadow Cat

Lollipop
P.S.: I'm not exactly sure if they are missing or they are to be considered enemies/NPCs. Anyways, I placed them here just in case.

Forgotten Candy (seen in FNAC: R)

Unknown Green Cat (what to do with it though?)
EDIT: maybe Clover could be a good WIP name for the little guy?
The joke animatronics

Nightmare Candy (technically unused and not a joke animatronic)

Phantom Candy

Funtime Candy

Funtime Cindy
Teaser/Beta skins

Hallucination Shadow Candy (WIP name)

Teaser Rat (WIP name)
The weird case of the Origami Cat

Why weird? I mean, it's this little fella right here, no? Well, this little fella is the reason why this post exists in the first place, actually. You thought this was just a checklist? Think again!
So, first off, no, this isn't the only version of the Origami Cat. There's another one in the games, notably, this one below:

We're looking. See how it's crumpled a little? Well, that about covers it, right? No. There's also an unused version hidden in the files, which is this one:

Oh, look, it has eyes now! Neat! So... we just place two similar skins of the same cat? Well, there's actually one last image in the same cutscene as the crumpled Origami Cat, which is much more interesting:

This, ladies and gentlebears, is Monster Origami Cat. And this is all we have of it (There's also a blinking animation, but it's not letting me upload it. The eyelids are black).
Monster Origami Cat: what to do with it
I showed you these last two images for a very specific reason. You see, we already have a Monster Cat, which looks like this:


Now, you can already see how there are some noticeable differences. Most importantly, eye placement and how Monster Origami Cat's eyes have a black line around theme, unlike these. There are also going to be texture differences due to the different material. So, essentially, no, it's not a copy-paste of Monster Cat.
So let's get to the chase: can a Monster Origami Cat be correctly designed with only the eyes and their placement in its Adventure form? My honest answer? As far as I can tell, yes. But it's hard, like always.
We have the Monster versions of both Rat and Cat. While it's nice to see the monsterification process here, they are made of the same materials and similar colors. So essentially, we get little from this. We do, however, have the monster version of Vinnie and no, I don't mean the FNAC 3 Vinnie, but the monster version of FNAC 1 Vinnie, which is this:

It's a very small pool to get from, but I think we get an intuitive understanding of what Monster means: in its most rudimentary essence, a realistic, scarier looking version of the animatronic, while keeping its essence. Something like Realistic Nightmare versions of the animatronics.
We do have an idea of what a Monster cat (a Monster version of a cat) could look like and we do have a body for Origami Cat with eyes. It's the unused render from before! So... what do you even do with this?
Three approaches, similar to the scrapped animatronics:
a character: another Monster Animatronic in the bag! This would be so cool to have, but again certain liberties cannot be taken while creating this. But imagine having a full Monster Team on your side! Fortunately, @LivingCorpse7
can design closely to Scott and Emil also designs similar to Scott, so the transition shouldn't be impossible, but again, this is basically designing a character based on a few abstract concepts. It's hard
an enemy/boss/NPC: more creative liberties can be taken, and at the end of the day it's a pretty inoffensive way to add the animatronic
an ability: at least it would be added in some way and this might be an even more inoffensive way, but I'd rather see it as one of the two above
I think this animatronic should be on four paws and be more animalistic then the other two, since Origami Cat resembles much more closely a cat.
For Origami Cat instead, similar proposals seen for its Monster counterpart can be made. It would be lovely to see these two characters come to life as team members (even obtainable towards end-game, like shop keepers in other fan games)!
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So... what do you think? Which animatronic among these would you like to see most? But most importantly, what do you think of Monster Origami Cat? Should it even be considered?
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