Isengard Orcs are those that worked for Saruman in the books and movies. They were lesser orcs, not Uruk-Hai or Orc/Man hybrids. They probably came from the Misty Mountains and Mordor. Their jobs were to build the buildings and minepits of Isengard, to scout Rohan and Gondor, to patrol and guard Isengard, to work the furnaces and other machines, to build weapons, to birth Uruks, raid enemy villages etc.. Known ones are the Orc Overseer, and the Isengard Informant. In the movies Grishnákh and Snaga work for Saruman instead of Sauron, putting them into this group.