Pot roast is usually something like rump roast or a round roast- inexpensive large roasts.

Typically you put it in a pot with carrot, potatoes and seasoning and spices. (Frequently a spice mix packet. Personally I’ll take a halved fennel bulb, a couple whole cloves, minced onion, salt and pepper, some red wine or vinegar. Keep it covered with water until tender then cook off the water at a low temp. You might want to add the carrots and potatoes later if it’s a large roast. Also consider using vegetable stock instead of water.)

Also another very adaptable staple is rice and lintels. It’s a whole protein, just cook them separate in 1:1 ratio, leave them slightly under cooked and finish together with “flavoring”- they’re pretty neutral on their own; so you can do pretty much anything you want here. (Onion, garlic, chili flakes/powder/chilis, quartered cherry tomatoes, and a splash of lime juice is a crowd pleaser.)