I have multiple regions in my fantasy kingdom one of which is largely high elevation tundra, ice fields and snow covered mountains (the ice fields and tundra are not in the same area of the region). I am looking for a valuable trading commodity in addition to the cold-hardy herds and the wool, felt and weaving that would come from them. Salt was something that occurred to me. They are thirty to fifty miles from a largely ice capped sea.
Continents float all over the place when a planet is forming, so latitudes don't actually matter when trying to identify what resources will be available where. I'm sure we'll be mining Antarctica as soon as we run out of local resources.
When two plates collide, much of the underlying rock gets shifted and turned over, kind of like the way plows uncover worms and bugs. This makes high elevation areas like mountain ranges and plateaus convenient places to find all sorts of exposed veins of ore.
They mine a lot of pink salt in the Himalaya mountain range on Earth. This is the result of plate tectonics and many, many tens of millions of years of uplift. While not quite as high, the salt flats of the Great Basin of North America (e.g. in Utah) are more than 1 km above sea level.
There is no reason that a fantasy kingdom couldn't have a similar resource.