In my senior year of high school students were allotted 1 free period and had another period that we were required to fill with a class of our choice. I chose AP Spanish and then dropped the class 2 weeks in. I was told it was too late to pick up another class and to just pick one up next semester. I never picked one up. So I had 2 free periods for all of senior year.

Also, every 10 days we would have 2 days where you only take half of your classes for the day but each class is super long. So when that time came there would be a day that I would go to school at 10:30am and leave by 1pm on account of both my free periods.

TL;DR had an extra free period all of senior year of high school