Currently hoboglins are the most known as slavers.
Slaves in the old empire were property of the empire first and their current masters second – so they were cared for in the sense of tools and equipment must be kept working. Medical care, proper nutrition, proper safety precautions were the standard. Outside of this, however, they had no rights and were almost universally used for the most menial or dangerous of jobs, jobs no one else would want to take. Much of the wealth of the old empire was both in slaves and due to slavery.
The goblinoids, particularly the hobgoblins, treat slaves as absolutely expendable and completely disposable. In goblin controlled lands they are forced to do back-breaking work and are exhausted often unto sickness and death. Ogres and trolls often keep slaves as food stores.