So you ask me to name one, and yet you've already come up with 3. So you're asking me for a forth. To what point when you've already come up with 3. You've already accespted that the category of things that are best done by government exists. You're just wanting to quibble about which items belong in the set.
Indeed, there are things that I think are best done by the government. They probably represent less than 10% of the actual government spending hence the ire at the 90% of the budget which could be drastically reduced.
And "just fine" isn't good enough. "As good or better than the government" is the bar.
Roads is an obvious one. Sure, there is the odd private road in most countries, but that's cherry picking the profitable routes. Private enterprise never provides a comprehensive road system like a government.
2/3rd of the roads in sweden are private. That's not what I call the "odd private road" by any measure. That's mostly small rural roads, not the most profitable kind where you can put a toll. And it works fine. I really don't see the need for the government here.
In many countries, public healthcare is only providing the absolute minimum, and things work fine. Sure, you can carpet-bomb the field and make everything public, but that leads to a waste of resource, and most countries cannot afford it - they get indebted more and more and while every country is in this situation everybody agrees that it is not sustainable.
Schools is another. Again, a few private schools doesn't cut it - that's cherry picking the offspring of the richest few. Private enterprise doesn't ever provide a comprehensive education system.
There are many more.
in the Netherlands, 2/3rd of schools are run independently. Granted, they are mostly government funded, but the money comes from somewhere anyways. Most revenue from the government coming from VAT, everyone pays for it, including the poor. The point is that the government doesn't need to handle the education, subsiding it (partially) is more than enough.
The global point is that in general, a field taken over by the government removes incentive by removing competition, and ends up costing much more for everyone. In general, except for the fields I cited, public money well spent is public money that A) the government has and B) that will significantly improve the field it is spent into. More often than not, none of these conditions are met, so the government shouldn't do them.