If we are in an argument, ask yourself: "does looking at my post history help your point or hurt it?"
Anything that is considered a utility or necessary for the function of a nation state, including all schooling, health care and other socially important services.
There have been attempts, but as far as I know they stopped due to safety issues. But I could be wrong.
How I read the question is what should be nationalised, not what else should be.