Felix, I may be telling you something you already know, but there is a lot of info on Ralph (pronounced Raff in England) Izard,in The South Carolina Historical Society publcations, Vol. II.It talks alot about The Izards and their properties The Elms,etc. in and around Charleston.One Ralph Izard arrived in South Carolina 1682 called a " Grocer and Gentleman of London".His Grandson (I believe), also a Ralph, was in the Continental Congress (against his will because he and his wife Alice Delancy Izard prefered London to So. Car. )and traveled with Ben Franklin to Paris to get the French to help the Rebellion.Now I know all of this is not exactly what you are looking for but there are Court records to search for references to Blacks and their dispositions in So. Car.I remember one about one of the Izards being arrested for taking one individual from another plantation and subsequently hauled into Court.Sometimes names are mentioned.
If there are Black communities with descendents of those who were able to escape from old Ralph, it might behoove you to get the Court records. Those Izards slowly diedout and all their vast properties are gone.