Hmm.. not counting the ones already confirmed to be in the game so far, and biased slightly in favour of the ones with fewer votes... I'm going to go with these:
Semi-Auto/Full-Auto/Revolver Shotgun:
Izhmash Saiga 12k, Ithaca Mag-10, Remington M1100
Break/Lever/Pump-Action Shotgun:
Winchester 1912, Remington 870, Ithaca 37
Machine Gun:
M249 SAW, L86 LSW, H&K 21
Assault Rifle:
AS VAL, M16, FN F2000
Battle Rifle:
FN FAL, M14 EBR, Kel-Tec RFB
Old/Fictional SMG (Pre-1960):
M1928 Thompson, MP 40, Sten
Modern SMG/PDW:
IMI Uzi, H&K MP7, AKS74U
Auto Handgun/Micro-SMG:
Steyr TMP, Beretta 93R, Spectre M4
Handgun:
H&K MK23, H&K USP, Walther PP
Revolver/Break-Action Pistol:
S&W 500, Colt Python, Taurus 44
Semi-Auto Sniper Rifle/DMR:
SVD Dragunov, Accuracy International AS50, M21
Lever/Pump/Bolt-Action Rifle:
Remington 700, Accuracy International AW, Barrett M99
Grenade Launcher:
Milkor MGL M32, GM-94, China Lake
Rocket Launcher:
RPG-7, M202 Flash, Carl Gustav M2
Flamethrower, Incendiary Device:
Dragons Breath, White Phosphorus Grenade, LPO-50
Melee:
Machete, (Bent) Pipe, Brass Knuckles
Pet/Ride:
Dragon?
