Shulker's Structures

Added swamp huts to swamps at a rate of ~1/150 chunks

Only useful thing in the hut is a couple torches and a bed. It's more for atmosphere.

Added towers to the hill and mountain variants of most biomes, along with extreme hills biomes.

Towers contain an enchanting table and a few pieces of glowstone, but nothing else of value.

Towers usually tower above the surrounding landscape due to their height and their tendancy to spawn on hills or mountains, so they're most useful for their view.