Howling Caverns
In the distance you hear a yell, nearly human, but lacking any true emotion. A chill is sent down your spine as you get the unnerving feeling of being watched. The darkness, growing darker; The cold, growing colder. How will you build, craft and survive in these less than lonely caves.
Desolate Crust
The surface has been all but destroyed, leaving nothing but endless banks of snow where civilizations previously thrived. The little life that crept below before everything was wiped out above began to flourish in their new habitats creating all new biomes to explore with vastly different climates. Additionally, you can throw yourself for a harder challenge by setting your world as a single biome world; My personal favorite is Frosted Caves.
The Goatmen
Sounding human to lure out their prey, the goatmen are ambush predators. Build defenses, reinforce and fight these ancient horrors, but beware, as they will not relent until they've won.