Suge Knight is probably the wealthiest of them all.
From Wiki
Marion Hugh “Suge” Knight, Jr. born April 19, 1965 is the founder and CEO of Black Kapital Records and co-founder and former CEO of Death Row Records. Death Row Records rose to dominate the rap charts after Dr. Dre’s breakthrough album The Chronic in 1992. After several years of chart successes for artists including Tupac Shakur, Dr. Dre, Snoop Dogg, Outlawz and Tha Dogg Pound, Death Row Records stagnated after Knight’s incarceration on probation violation charges in September 1996.
Jay-Z and Dr. Dre are probably worth more.
Probably P Diddy as well.
Dr Dre sold Beats audio to Apple for a billion bucks or something