Biome Specific Ore, basically different types of ore will be able spawn in different biomes.
Fire Biome (Fire Related)
-Emberstone, Magma Core
Acid Biome (Radioactive/Poisonous)
-Venom Crystal, Corrosium
Frozen Desert (Ice related)
-Frost Quartz, Permafrost Iron
Blood biome (Blood related)
-Bloodstone, Crimson core
Werewolf Woods (Night related)
-Moon Silver, Lunar Shard
Unicorn Desert (Fantasy)
-Prismalite, Harmony Crystal, Starlight ore

And then you can use these ore to craft different items in the future. For example crafting a sword with Lunar Shade material would make it stronger during night time. Or crafting a sword with Permafrost iron that can freeze enemies. There's so much possibility you can do.