Whisk the egg, ketchup, mustards, oats, Worcestershire sauce, salt, pepper, and minced onion together in a mixing bowl with a fork.Add the ground beef and use your fork to incorporate. Be careful not to overwork, mixing too much can result in tough meatloaf.Using your hands, form the mixture into a loaf and place on a cookie sheet.Bake at 350 degrees for 50 min.While the meatloaf is in the oven, mix the sauce ingredients together.Remove meatloaf from the oven, skim off the fat, and pour sauce over the top. Bake for 10 more minutes or until meat reaches an internal temperature of 160 degrees Fahrenheit.