There are things like Labrador Tea (delicious!), Wild Suk (Artemisia), Chrysanthemum, Wild Rosehip, Wild Mossberry (or crowberry), Cranberry, Cloudberry, Juniper etc. All single ingredient herbals...and that's naming only a smattering of them.
You can find some of these at Acquired Taste Tea Company in Edmonton, AB (under the brand Northern Delights Inuit Tea) and Dao Tea in Richmond, BC. Or your local forest.
Catnip with a leaf of Stevia would be yummy, I think!