Corn beef hash and Shepherd's/Cottage pie are two great one dish meals. They have your meat and potatoes, and then you can add any additional vegetable you like into the mix. This way you get all your main food groups into your main meal. They are easy to make and very comforting meals.
I love a one-pot meal! Soups are great like that, you can just throw everything in and leave it to cook. But my favourite one-pot meal is a tofu hotpot - if you don't like tofu you can replace it with meat but the flavours are rich, it feels nourishing, and it's full of protein and essential vitamins and minerals.
Single pot? How about single pan? Lasagna! I love Italian food and to me there are few things better than a good lasagna. It doesn't matter what kind, beef, pork, veggie, lamb, crocodile, they are all good.