Do you mind categorizing the different styles/artists of the 90s?
There's no one exact categorization but there are many styles imo
The aggressive, grimey NY hardcore rap like Mobb Deep, Capone'N'Noreaga, DMX, Raekwon, Kool G Rap, Onyx, Smif n Wessun, etc...
If you don't like it too grimey but still like street rap or the boom bap sound then there's less grimey edition like Nas, Gang Starr, Ghostface, Big Pun, Masta Ace, Big Daddy Kane, etc...
if you like a little more poppy but still hip-hop he try Biggie, Jay-Z, Mase, etc...
then there's the g-funk westcoast sound like Snoop, Dre, BG Knoccout and Dresta, Kam, Mack 10, WC, Tha Dogg Pound, etc...
if you don't fukk with g-funk but still like funky hip-hop then there's EPMD, Redman, Spice-1, 2Pac (mostly), early Ice Cube, Da Lench Mob, etc...
if you like angry chaotic, political stuff with a lots of samples then there's Public Enemy
then there's "horrorcore" like Brotha Lench Hung (also g-funk), Gravediggaz, Geto Boys...
choppers like Twista or Bone Thugs...
heavy Houston hip-hop like UGK, Big Moe, DJ Screw , Z-ro,
alternative, jazzy, conscious guys from all over the USA like ATCQ, De La Soul, Goodie Mob, Outkast, Souls Of Mischief, Common, The Pharcyde, Brand Nubian, etc...
and even inside those different styles there are pretty big differences between different artists and different years. You can probably hear the difference between early '90s and late '90s stuff