Grandmaster Flash
Sister Souljah....
Public Enemy....
Tupac....
Kool Moe Dee
Brother Keita,
Grandmaster Flash is not a rapper but a DJ. So I take it you mean the group, in which case if could be Melle Mel, Scorpio, etc.
Other than that, my 5 cents...
Rakim
KRS-One
Chuck D
Sistah Souljah
Tupac Shakur
Peace.