In "Glorious Five Year Plan" (S4E04), what appears to be a Beretta 92FS is seen in a police officer's holster seen while filming a television commercial.
Browning Hi-Power
A young Grace Mallory (Sarah Swire) carries what appears to be a Browning Hi-Power during a flashback to 1986 in "Barbary Coast" (S3E03).
Colt M1911
Soldier Boy (Jensen Ackles) uses a Colt M1911 as his sidearm, most notably in "Here Comes a Candle to Light You to Bed" (S3E07).
Colt M1911A1
Billy Butcher (Karl Urban) carries what appears to be a Colt M1911A1 pistol while attending a gun show in "The Only Man In The Sky" (S3E02). He also uses it in the garage shootout later in the episode.
Glock 17
The Glock 17 is seen in use by Frenchie (Tomer Capon) and numerous background characters.
IMI Desert Eagle Mark XIX
Gunpowder (Sean Patrick Flanery) is seen with a IMI Desert Eagle Mark XIX pistol, apparently carrying two of them as his sidearms, notably using it in "The Only Man In The Sky" (S3E02).
In "Barbary Coast" (S3E03), Sandanista troops attacking Soldier Boy are armed with AK-74s.
AK-103
The Russian soldiers in "Glorious Five Year Plan" (S3E04) are seen with AK-103 rifles while confronting the Boys.
Czech Small Arms Sa vz. 58 Compact
Mother's Milk uses the CSA Sa vz. 58 Compact against the Russian troops in "Glorious Five Year Plan" (S3E04).
Colt Model 733
In "Barbary Coast" (S03E03), the Colt Model 733 is seen in the hands of the Contra rebels.
Custom AR-15 variant
Gunpowder is seen with a customized short-barreled AR-15 slung over his back in "The Only Man In The Sky" (S3E02), although he is never seen actually using it. The carbine is fitted with a custom muzzle brake, a Magpul PMAG, Trijicon TA01 ACOG sight, and custom wooden handguard, pistol grip, and fixed buttstock. The resulting weapon bears a vague resemblance to the Colt Model 607, though with the obvious difference being that Gunpowder's carbine has a flat top receiver.
Machine Guns
M2 Browning
Gunpowder fires a Browning M2 .50 BMG, mounted on a jeep in "Barbary Coast" (S3E03).
Launchers
Carl Gustaf M2
What appears to be a Swedish Carl Gustaf M2 recoilless rifle is seen wielded by Soldier Boy during the 1980s in "Barbary Coast" (S3E03).
M252 Mortar
What appears to be an M252 Mortar is among the weapons seen in the contra camp in "Barbary Coast" (S3E03).