Favorite uncommon herb to use?

I am an avid collector of rare and uncommon herbs and I am curious what you alls favorites are. Anything counts roots, leaves or flowers. Any intention. All I ask if that when you comment you say what intention and in what way you prefer to use the herb. I’ll go first.

One of my favorite herbs (because I really can’t just choose one) is Mandrake! Mandragora officianalis is most often used for good fortune but my preferred intention is astral travel. It is one of the main ingredients in my witches flying ointment.