Black

Black people are a race apart of the Humans, having a high number across the entire world (My G's get shot by marines everyday). They have suffered from segregation and racism in the history of the world, mainly from their own species (Human Beings) rather than other races in the One Piece World.

Special Traits
Other than stealing your girl, high intellect and also skill with a firearm there are no other real special traits.

Slavery (Oh boy....)
Since they are apart of the human race and show no other special trait other than their skin colour they are also sold for 500,000 on the slave market though they are not sold as much as other races in the OP world.