Preheat your oven to 250ºF/120ºC. Place your leftover meatloaf slices in a small shallow dish. Sprinkle each piece with 1 tablespoon of beef broth. Cover the dish with aluminum foil, place it in the centre of your oven and cook for 20-25 minutes. Turn the air fryer to 350ºF/175ºC and line the basket with baking paper. Spray both sides of your meatloaf slices with oil spray and reheat for 4-5 minutes. Preheat the toaster oven to 350ºF/175ºC, place the slices on a metal rack, heat for 3 minutes, flip, and heat for an additional 2 minutes. For the microwave, cover the slices with a damp kitchen paper, reheat for 1 minute, turn over, and heat for 1 minute more. If not hot enough, reheat in 30-second increments at 50% power. For a skillet, add oil and beef broth, place the slices in, and cook for 2 minutes on each side. Finally, for steaming, place in a basket over simmering water and steam for 3-4 minutes.