Lot of good guesses:
Cru
Spooks
Adam F as a Hip-Hop producer (That Khaos album was dope)
Megahertz as a Hip-Hop producer
Canibus
Papoose
Saigon
Jae Millz
Kid Daytona (I wouldnt call him a flop but given the peers he came up with I thought he would be bigger)
Freddie Gibbs (same as above. It might not be too late)
Queenpen
Pras as a solo artist (didnt like him but I thought he would have a successful solo career like the other 2 off of Ghetto Superstar)
bis still doing his thing. i expect more from jae millz as well found out that he was in a group with this dude presto. pras should've been right behind wyclef