Even the main ingredient can vary. Some recipes call for ground deer, elk, or moose meat. Lentil and nut loaves can be as tasty and satisfying as meat. For the liquid element, important in keeping the loaf moist and preventing it from tasting like a giant, overcooked hamburger, substitute beer, ketchup and water or just plain ketchup, canned tomato or mushroom soup, applesauce, chicken stock, canned tomato sauce, or tomato or V-8 juice. Instead of soft bread crumbs, use oatmeal, dry cereal, slices of bread softened in the liquid, crushed crackers, stuffing mixes, bulgur, or cooked rice.
Meat loaf can take a substantial amount of seasoning.
Adding herbs and spices gives it character. Along with salt and pepper, try horseradish, mustard, anchovy paste, hot sauce, basil, cayenne, celery flakes, curry powder, dill, ginger, nutmeg, sage, savory, or thyme. Improvisation doesn't have to stop with what goes into the meat loaf. Some cooks swathe loaves with slices of bacon or douse them in ketchup or tomato sauce before baking, which results in a tasty glaze or crust. Ketchup is commonly served with meat loaf, but you could also serve it with brown gravy, perhaps with mushrooms or onions.