This is a sub-page of Killing Floor.
Weapon Models#
IJC's weapon pack - original mutator version#
Tripwire accidently left in the original versions of the IJC weapons' static meshes (IJCWeaponPackStaticsW2). These are used with the original whitelisted weapon pack mutator. These are not the same models as the released version and use their own textures. These older models are much higher fidelity with some small detail differences.
Mac-10 Extras#
2 extra Mac-10 models exist, one is almost identical as the normal one, but has messed up arm materials, the other has no gun material, and the silencer is moved behind the viewmodel. Perhaps an unsuppressed version of the Mac-10 was planned at some point?
Additional ZED-GUN Parts#
In the final Moonbase map the collectables are a general capsule for holding ZED-GUN parts, however in the ZED_Pieces static mesh package, you can find every single piece of the zed gun as its own model, implying they were all originally going to be separate pieces. This was likely changed because some of the pieces are very small and would be hard to see. It's also interesting how they named every single piece of the ZED-GUN.
Gore#
Early Clot Gibs#
You can find early more detailed Clot gibs, They are parts of the head split up, but lack a proper blood material on the inside so just use the normal Clot material which does not seem to be correct. These were presumably cut for this reason. You can find commented out lines for precaching these models in the ZombieClot class.
Circus Gorefast Head#
The Sword Swallower does have a decapitated head mesh. This was most likely not used due to aesthetical reasons, though gameplay wise, the Circus Gorefast can be beheaded but visually will retain its head.
Unused 3D Blood Splash Effect#
You can find models of 3d blood splashes in kf_gore_trip_sm static mesh package. You can find commented out references in the KFBloodPuff class all in a big section labeled "KF Blood Spray (normal shot effect) New 3d Style Style" that has all of its contents commented out. These seem to have been supposed to show up when shooting a zed, however with this code uncommented whatever the intended effect was supposed to be seems to not work either do to changes or maybe it never ended up working. Despite no longer being used, they still get precached into memory though other code. They have no textures assigned anywhere in the code and may have had them removed or never made.
Decapitated Player Heads#
Almost all playable characters have a decapitated head model, though most of these are just using the preexisting model's heads with a gore mesh attached at the neck, Masterson is the only character with a unique expression. It's unknown why these were never used, despite the gore static mesh file being updated by adding in new heads whenever a character would release.
Note: Some do get used as props in levels.
Early Trader#
You can find what seems to be an early version of the Trader in the files. It replaced the KF Mod model in the files and doesn't seem to have its own textures anymore. She has an idle animation of her hunched over a table.
It seems to have a lot of missing or inverted faces, so it is presumably a very early model. It is hard to tell many details without textures, but she does seem to have 2 pistols on straps.
Trader Camera#
A static version of the normally skeletal mesh Trader camera, it also has a little bit of bloom added the the light on the front. 
Merlin HC3#
A static version with landing gear out of the normally skeletal mesh Merlin HC3. 
KF_EngineTest#
You can find a static mesh package called KF_EngineTest that has static model versions of a player soldier and most of the zeds minus the Fleshpound and Patriarch. This is was obviously used to test something with the engine. Also worth noting it has the Husk, so it was some point after launch this was created. All of them are in A-poses except for the crawler who is in a crawling pose.
Map Models#
Abusement Park#
A few unused meshes inside FreakCircus_SM_Two.
Aperture#
Killing Floor was a part of the Potato Sack, and features a crossover level with Portal. Inside the mesh package you can find the Portal 2 GLaDOS head, this model goes completely unused. 
Bedlam#
You can find a single doorframe variant that goes unused in Asylum_SM.
Biotics Lab#
A very small door model can be found in KillingFloorLabStatics that goes unused and is not from the mod.
Hell Ride#
There are a few unused models in the Hellride_sm static mesh package.
Toy Master#
You can find a version of the dollhouse that has no table under it. You can also find a mesh called Defense Jewel, it may have perhaps been planned to show up in or around the toyboxes, as they are the only thing you defend.
Manor#
In the KillingFloorManorStatics package has an unused brick tunnel model.
Moonbase#
The Moonbase static mesh packages include a lot of unused models in a seemingly different style, which indicate it might have originally been planned to have a different, less retrofuturist look for the map. There's also more detailed mesh versions of some terrain, maybe indicating you could walk on the moon itself too at some point.
Office#
In the OfficeStatics package you can find an unused window model that has the Horzine logo on it.
West London#
Some general London models are in the KillingFloorStatics package. The ones here were never in the mod and were added during retail development and never used.
Wyre#
A few different things can be found in WyreStatics.
