In the UK you can get John West Light Lunches, which are a kind of tuna salad that I like very much. They come in a shallow foil hexagonal tray and don't need cooking. Contents include potato, sweetcorn, peppers, onions etc. I eat roughly 2 a week. They keep for several years so are a convenient food to stockpile at home for sheltering in place. I do keep one in my car as well, but I don't know how long they last in that environment.