Biome Ideas (Late or Early)

Snow Biome/Antarctic Sub Biome: Snow biome features dark wood, with a fancy furniture/housing style, enemies drop special crafting material like passage enemies, no special ore, antarctic sub biome features alien monstrosities and a horrifiying new boss.

Stillness/Spiritual Realm: Think of the inside of Sin from FFX. The entire biome is lit up. The walls are invisible but can be mined, but inside could be powerful enemies or other wonders. I was thinking of a mind bending kind of biome, where you think there's nothing in the biome when you walk inside it but you hit a wall, and only until after you break the wall do you see that the biome isn't empty.

Nightfall Biome: We know that light does reach wherever we are underground, so what if there is a part of the world that's perpetually in night, and we see the evidence of that by stars reflecting in the water? Enemies can be inspired by cryptids or monsters from movies. New campy weapons and gear.