To name a bit:
Sage Francis
People Under The Stairs
Atmosphere
Sole
Alias
Murs
Jedi Mind Tricks
Eyedea and Abilities
Living Legends
Bluprint
Buck 65
Brother Ali
All Natural
Louis Logic
Gangstarr
Mr Lif
El-P
Aesop Rock
Immortal Technique
RJD2
Edan
Wu-Tang
Linkin Park
Rage Against The Machine
Sublime
Queen
Peter Tosh
Bob Marley
Sam Cooke
Toots and the Maytals
Jimmy Cliff
Tony Tribe
The Skatalites
Dandy Livingstone