As much as we love glitches, exploits, cheats, and other OP stuff, I mostly just love mountains. And so I present to you how to get 100% map completion on two zones.
Whispering Caverns (Area 2):
Jump to this spot to fall down.
It's not actually possible to fully unshade this region, but there's a bunch of cool things to climb, and you can go way beyond the black area.
Now, in case you're wondering if the Icespire Mountaineer achievement will be obtainable by this method, I don't know yet. I have literally climbed to the highest point on 30% of the mountains in Icespire and was met with a bittersweet view of an invisible wall. If anyone finds a way before I do, feel free to post it, otherwise I'll update this post when I do.