Slaves rarely got a day off, with the exception of Sundays. However, which holiday was a given to slaves as a day off?

Christmas

Explanation:

They received material goods from their masters

In many places, it was customary to give slaves one day of the week off, so that they could farm their own garden plots. This was beneficial to the slave owners for two reasons - first, it freed them from the responsibility of feeding the slaves. Second, they made money off the gardens they plotted.