There are as many meatloaf recipes as there are cooks. Some folks use just ground beef. Others use some combination of beef, pork, veal, turkey, chicken.
In general meatloaf should contain one or more eggs to act as a binder to hold the loaf together and breadcrumbs, oatmeal, etc. to give it the right texture and absorb some of the liquids.
Seasonings, herbs, spices, cheese, BACON!, and some type of tomato sauce are often used.
I'd bet there are hundreds of meatloaf recipes on this site to choose from.
Here's a recipe to get you started:
MEAT LOAF
1 Onion
2-3 Garlic
⅓-½ Green Bell Pepper
4 Mushrooms
½ tsp Thyme, dry
¼ C Parsley (2 Tb dry)
⅓ C Romano Cheese, grated
2 Lb Ground Beef (85-88% lean)1
½ Tb Salt
⅛ tsp Black Pepper
⅔ C Bread Crumbs
1 Ea Egg
¼ C Ketchup
1 Tb Soy Sauce
⅛ tsp Cayenne Pepper
Preheat the oven to 350º F.
Place the first seven ingredients into a food processor and process until almost pureed.
Place the meat in a large mixing bowl; add the vegetable mixture from the food processor and the remaining ingredients.
Thoroughly combine the ingredients.
Pack the mixture into a loaf pan to shape the meat.
Cover a sheet pan with foil or parchment paper.
Invert the loaf pan onto the sheet pan and unmold the meat loaf.
Insert a thermometer probe into the center of the loaf and set to 155º F.
Bake until the set temperature is achieved, about 1 hour and 15 minutes.
Remove the meat from the oven and rest it, covered, for 10-15 minutes before slicing.
NOTE: You may use a combination of ground beef, pork, veal or lamb.