>>64133395 (OP)
Depends on which city you're talking about, the wealth of the gang, the ethnicity of the gang and most importantly what era of the 90s because early 90s is going to be different than late 90s.
I think it would be fair to say that .38 special snub nose revolvers (particularly the S&W Model 36), 12 gauge sawed-off shotguns, Browning Hi-Powers and Colt 1911s were ubiquitous for the whole decade.
In the early 90s you might see the Beretta 92 or Glock 17 but neither of them would be common. Later on you'd see more modern handguns like the Smith & Wesson 5906 and Glock 19 work their way in, but I think the Model 36 takes precedence over all of these.
If they were rich or well connected enough, they might have TEC-9s, MAC-10s, MAC-11s, an Uzi or even Norinco AKs. The average gang member likely never touched one of these, though. Even if they had heard about them and idolized them.