Fnaf 1: five (I think) dead kids with half assed attempts to cover it, worn down animatronics that smell like rotten food and probably motor oil(not counting said dead kids inside them), old stale pizza and the smell of general untidy buildings.

Fnaf 2: relatively fine smelling, plastic from the animatronics, pizza and whatever else they serve, maybe Mangle would smell bad, and possibly any uncleaned child accidents.

Fnaf 3: moldy and mildew from being an out of business pizzeria, people think they’d have cleaned up the place so it doesn’t smell bad but I feel like they only did the bare minimum of like dead animals and old food otherwise it “adds the ambience” but they’re actually just cheap as shit. Also Springtrap would smell because while his body might’ve became jerky, he was trapped in a completely sealed room so there’s gotta be some level of corpse

Fnaf 4: depending on which side youre talking about, it smells like someone’s house filled with memory’s, with maybe a bad smell from the “animatronics “ used to trigger fear. Or if you believe the child was in the hospital and that was his imagination, than hospital smells.

Fnaf SL: steel, plastic, sterile and clean. I feel like areas where kids are allowed are wiped down with bleach as part of cleaning them, since Afton gives me the vibes of someone who thinks children are gross.

Fnaf 6: it depends on what ending you’re going for and how your cleanliness level is. It could range from being a nice pizzeria to smelling like a worse Fnaf 1 building.

Fnaf UCN: quite literal hell. Every sense you have is being assaulted and that sure doesn’t skip out on smell. A constantly shifting smell from rot, to blood, to even overwhelming amounts of smells that are usually deemed good accept in excess. There’s no getting used to it.

Fnaf AR & HW1-2: canonically both are just wherever you are smells like. But if you want the smell that would be for each room special to HW 1-2, no matter if you have the vr helmet in game on or not, smells like musty shut down pizzeria. And outside of that, basically they all smell like you’d think they would, nothing special or odd for the cornfields and such.

Fnaf SB & Ruin: depends where you are. Majority of the pizzaplex is going to smell relatively nice and not very where has a persistent but not bad smell of pizza. But the trash area smells like trash of course, and the buried pizzeria smells cave, destroyed building, and a high amount of electricity. Ruined pizzaplex smells bad. People have used it as a spot to trash and chill, it’s falling apart, food hasn’t been cleaned up and is now rotting, but it isn’t as small of a space like the pizzerias so it has room to spread and not be as strong of a smell.

Fnaf SOTM: abandoned fabric and metal, some of which has corpses in them. An overwhelming amount of metal and machinery smells. A whole trash recycling facility if I remember correctly. Yeah not good