Preheat an oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.
Mix the ground beef, ground turkey, zucchini, onions, green bell pepper, egg, Worcestershire sauce, Cheddar cheese, bread crumbs, and ranch dressing mix until well combined. Form the mixture into a loaf in the middle of the prepared baking dish.
Stir together the ketchup and steak sauce in a small bowl. Pour the sauce over the top of the meatloaf. Bake in the preheated oven until no longer pink in the center, about 1 hour. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).