Volcanic Biomes (Four of them)

I propose a few Volcanic Biome types to be added to the game. First of course is the Mountain Crater. A mountain with a crater at its top. There would be two main variants. Active, and Inactive. Active Craters have a Lava Pool inside, or magma cascading down its slopes. Inactive has Obsidian and Basalt mixed in with stone sparsely in its crater. Next would be a cave biome existing below mountains. The Magma channels. This would be a biome existing above the lava lakes. It would consist of vertical and horizontal tubes of magma. Magma rivers would also exist in the biome. This biome should have a sinister look with stalactites and stalagmites in the biome. Third would be a Caldera, or a massive Lava lake in the overworld. This would be like the Lava pools found around the surface but much more grand in scale. I think these Caldera's of lava should mostly be found in Savannah biomes. Last Biome would be a deep sea biome. This would consist of thermal vents and chimneys of hot gasses like sulfur. Some of these Vents are called "Black Smokers" due to the large black ploom of smoke they release into the water. Some deep sea shrimps feed off the heat and sulfur of these vents.