We used to have a huge underground scene here. I don't really pay attention to newer rap cuz it sucks but here's a list of some really overlooked L.A. gangsta/street rappers, some that still rap, some that don't.
B.I.B.
BG Knocc Out
Black 9
Black Knights (part of Wu-Tang but from compton & long beach)
Blak Czer
Boss
C.E.B.
Coolio Da Unda Dogg (yes he IS from Watts, not the bay)
CPO
Dazzie Dee
DBA Flip
Delinquent Habits
Duce Duce
Fo Clips
Gangsta
Gonzoe
Green Eyez
Hi-C
I Smooth 7
Insane Poetry (gangsta/horror rappers)
Juvenile Committee
Kam
Kausion
Keitarock
Killafornia Organization
King Tee
Kokane
L.A. Mack
L.B.C. Crew
Lethal
Lil 1/2 Dead
Lil Chill
Lil Rachett
Lime Block
Loon-E-Toon
Menace Clan
Mr. Money Loc
Mr. Short Khop
Murdersquad
OFTB
Penthouse Players Clique
Perfec
Poppa LQ
Road Dawgs
Set Tripp
Sinister
STR8-G
Swoop G
The Body Snatchaz
The Relativez
True Blue Niggas Off The Street
Volume 10
Watts Gangstas
Young Dre
Young Murder Squad
Every rapper/group I listed comes with heat. That's whats different between L.A. and the bay. You might have hundreds of different rappers droppin' cds every year but how many of those are actually worth listening to? Quality not quantity. I'm not saying that the bay is weak because some of my favorite cds are by rappers from the bay but the market up there is saturated with garbage.