I have a huge supply of sunroots (AKA Jerusalem artichokes, AKA fartichokes) that aren’t “exotic” but aren’t found in the supermarket.
They’re a native North American plant, basically a sunflower that produces loads of little knobby potatoes.
You leave them in the ground all winter until you need them, they’re pretty much the perfect survival food.
Persimmon isn't "exotic" either but it is exotic. I'm really surprised more people don't grow it. (Not quite yet. That spot OKRuss rototilled for me will have a couple persimmon plants in it.)
Fig grows well for me but it is in a really sheltered area. I'm wanting to plant a few more of those next spring also.