Many characters throughout the film use Taurus PT92 pistols, most notably T-Bird (David Patrick Kelly), the leader of the gang that kills Eric Draven (Brandon Lee) and his fiancee. Eric himself later wields T-Bird's PT92 in a shootout at Top Dollar's (Michael Wincott's) club. Some of the gangsters in the club also use them, and Eric uses several other discarded PT92s (sometimes akimbo) in the course of the shootout.
Top Dollar himself also uses what appear to be a pair of stainless PT92s during the climactic shootout in the church. They're never shown very clearly, but a handful of brief glimpses of the guns reveal them to be PT92s.
Smith & Wesson Model 629
Funboy (Michael Massee) uses a Smith & Wesson Model 629 .44 Magnum revolver as his weapon throughout the film, which he uses to kill Eric Draven in his apartment. After Eric kills Funboy, he takes the 629 for himself, and is seen using it in several scenes (most notably the shootout in the club, where he wields this gun "akimbo" with T-Bird's Taurus PT92). This is most likely the gun that killed actor Brandon Lee in real life.
Beretta 92FS
Sergeant Albrecht (Ernie Hudson) uses a Beretta 92FS as do nearly all of the other police officers in the movie. They can be most easily told apart from the Taurus PT92s because of their slide-mounted safeties.
Mossberg 500 "Cruiser"
At the pawn shop, when he is trying to get back his fiancee's wedding ring, Eric Draven uses a nickel plated Mossberg 500 "Cruiser" shotgun. He ignites spilled gasoline in the shop by firing this shotgun at the front window, after pouring all of the shop owner's stolen jewelry down the barrel.
Calico M950
Grange (Tony Todd) is seen in the film using a Calico M950A pistol as his weapon of choice. Top Dollar also briefly uses this gun to execute a pawn shop owner in his club.
Calico M900
Grange is also seen using the larger Calico M900 carbine fitted with an M951 foregrip and a laser sight. This is the gun he uses to shoot the titular Crow of the film (which gives Eric Draven his power).
"Bye-bye, birdy..."
Mossberg 500 Bullpup
Grange also uses a bullpup shotgun that seems to be fitted with a Muzzelite stock when he's about to execute the Crow: "Bye, bye, birdie." However, he is then distracted by Sergeant Albrecht, who shoots him in the shoulder and then takes this shotgun after Grange drops it.
IMI Desert Eagle
Skank (Angel David) uses a two-tone Desert Eagle Mark I as his sidearm, which is seen when he and the rest of the gang are getting drunk in a bar. At least one of the gangsters in the club also uses one.
MAC-10
Several of Top Dollar's thugs use MAC-10 machine pistols during the fight with Eric in the loft above the nightclub.
Heckler & Koch MP5A3
At least of Top Dollar's gunmen carries a Heckler & Koch MP5A3, which seems to have a vertical MP5K-style grip mounted under the barrel (but the gun is definitely not an MP5K).
Revolver flare launcher prop
Albrecht holds this bizarre five-shot contraption in his left hand when he attacks Grange and Top Dollar. It appears to be a custom prop firing crimped shotgun shell blanks. Note that the cylinder is out of alignment as the 'weapon' fires. The 'flare' itself is a separate special effect running on a visible wire.