Originally posted by Weaver:

I have golem crystals because they are from a finished biome, but I completely avoid unfinished biomes. I feel collecting the stuff now would be cheating myself out of the full experience of those biomes later, and the devs made mention that when those biomes are fully added explored sections may not update but unexplored should.

Rn the Mistlands doesn't give you anything, there are ancient roots which can't be chopped down yet, presumably will be another wood type for better stuff. Mistlands is honestly fun to creep around in, very spooky atmosphere and a great place to setup an outpost, the darkness makes it much harder for the player to be spotted by any patrols wondering in from other Biomes.