Macaroni and Cheese.
I can't really think of any food that I would ABSOLUTELY not eat cold, if circumstances (like a power failure) were such that I could not easily warm it.
basically. anything that comes out of a can.
I can eat everything cold but meat sauce is something which shouldn´t be cold when I eat it.
Cold Roast Potatoes , they taste funny yuk!
Any food that's meant to be eaten hot.
And other hot foods.