Adding up to the existing "Forest" and "Underground Mushroom" biomes I've already shown you, there's a couple of more. This one is sand and has scarcely a few special properties besides comodos, sand crawlers and cactuses (along with spawning mummies during Hardcore mode).
This one is corruption. A highly dangerous place full with vicious monsters that not only dig themselves through blocks & walls effortlessly but also feature flying, deadly monsters at any time. It has large pits here and there which either lead to treasure chests or Shadow Orb / Beating hearts.
Destroy them with a hammer and special events will occur, like bosses spawning or meteorites falling from space and onto your world. The Shadow Orbs / Beating Hearts also tend to be a reliable place to get guns as long as your pickstone is strong enough to break the surrounding blocks or if you have bombs/dynamite to blow yourself through. There is a mirror opposite to this world called Crimstone. It is almost equal in every way except It's red and feature slightly different mobs, most restricting themselves to ground/walls.
This is the world's dungeon. There are always only one and they are incredibly large, sprawling in a huge network of tunnels underground. In this case, my dungeon spawned as a Pink color. They almost always vary in size depending on worlds. You need to kill a certain boss outside every dungeon by talking to an NPC standing outside them at night.
You can only find certain, very exclusive items down in dungeons although you need to kill the surrounding mobs in order to get keys to open the chests and once you unlock Hardcore mode along with other goodies, the dungeons will change types and will gradually get harder to explore.
This is the Jungle Biome. It is one of the biggest, singular biomes a world can have due to the gigantic underground areas beneath them, referred to as "Underground Jungle".
They offer very tricky landscapes with deadly monsters that almost always have some kind of way to poison you while swarming & hitting very hard. In return to this, Jungle Biomes offer some very big rewards in the treasure chest below, sometimes being located in the grass and sometimes being in golden temples. They are also the only place to get the Chlorophyte Ore, the best and most important ore in the game required to make the hardiest of armors.
This is the "Ocean" Biome. It is currently overrun by Corruption (which spreads to other biomes like cancer), not the best example since It is normally filled with just sand but it showcases the dynamic and random elements of Terraria.
This Biome is the only place where Sharks can spawn.