It seems meatloaf is available with two sauces: Tomato-based, or brown gravy.
The tomato sauce is usually ‘baked on’, in that it adheres to the top and sides of the loaf; though there is also a less viscous sauce that can be spooned over. Tomato-based sauce might be catsup, tomato paste, tomato sauce, or other sauce that is primarily tomato. The brown gravy is… Well, brown gravy. Or onion gravy.
Which do you prefer?