So hard right is the same thing as far right. If you google it, 'far right' comes up. In fact, 'hard right' isn't really a thing.
The reason I would not call libertarians hard right is not because that's the wrong place to put them on some abstract political spectrum, but because the term 'far right' has certain connotations that, whatever their flaws, simply do not apply to libertarians, so using the word conveys the wrong impression. Do libertarians sit around thinking about how they can best exterminate race enemies? No. So I'm not going to call them far right, because that's what someone will think I mean if I use that phrase to describe them.
Terms like "far right", "hard left" etc have value in that they are useful short hand in that they tell you something about what someone's politics are, but trying to put them into some abstract symmetrical framework is a mugs game, people's political views are far too complex to be put into a framework like that, or at least two complex to go into one with just two axis.
When the sky above us fell
We descended into hell
Into kingdom come
Libertarianism is just the goth approach to various other mainstream ideologies.
"One day, we shall die. All the other days, we shall live."