At least one Glock 17 is seen in the hands of a deputy sheriff.
Beretta 92FS
A Beretta 92FS pistols were carried by various Sheriff's Deputies as their sidearms.
Revolvers
Colt Trooper
A .357 Magnum Colt Trooper appears in the film several times, the first time in the holster of Trooper Gideon (Jon Beshara) and later at the County Sheriff's station. (These are educated guesses, gleaned from multiple viewings of the clips, however all the scenes with the revolvers are dark and hard to make out).
Unknown Revolvers
Several unknown revolvers are seen in the Police massing scenes, however, they appear to Smith & Wesson types, judging by frames and ejector shrouds.
Shotguns
Double-Barrel Shotgun
The Cat Lady (Eileen Brennan) retrieves a double barreled shotgun from her house when she notices The Creeper posing in front of her scarecrow in the garden. She fires a shot at it but misses and it flees into her house, she then goes after it, fires two more shots from within before being killed by the Creeper. Apparently the shotgun was loaded with high explosive rounds judging by its effect on the scarecrow post.
Winchester Model 1200 Shotgun
The Winchester Model 1200s were used by state police officers who are killed by The Creeper in their patrol car. The Model 1200 is also used later (with rifle sights) by the deputies at the County Sheriff's station.
Assault Rifles
Colt AR-15 HBAR
A Colt AR-15 HBAR rifles (more likely being that they are police rather than Military) are used when the deputies don Riot gear and confront the Creeper at the films' conclusion.