Preheat oven to 375 degrees F. Line a large baking sheet with parchment paper.
Open garlic bread, separate halves, and place on baking sheet with butter side up.
Bake for 7 minutes. Remove from the oven.
Spread half of pizza sauce on each half. Evenly divide the pepperoni, sausage, and ham between the 2 halves. Top each with even amounts of the veggies. Sprinkle 1/4 cup of the mozzarella cheese on each half.
Return to the oven and bake 6-7 minutes, until cheese is melted and bread appears light golden brown on edges. Remove from oven.
Sprinkle the remaining cheese on each half, and set back in the oven about 2 minutes, for this cheese to melt.
Transfer bread to a cutting board and allow to set about 5 minutes.
Cut into pieces of desired size.