Dynamite

This is the workhorse for moving a lot of stone in a hurry before hardmode. Throwing an armful down a shaft clears more ground per second than any early pickaxe, and it works underwater, so flooded caves stop being a problem. The catch is the long fuse. You have to throw it where you want it and then get clear, which makes it bad in tight vertical spaces where the stick lands back at your feet.

Nothing between you and the charge softens it. Hiding behind dungeon brick or any other blast proof material stops the crater but not the hit, so a wall you assumed was shelter still puts you on the floor. Plan around distance, not geometry.

The area that hurts creatures is a square, and it reaches further out than the round hole that actually gets dug. That gap catches people constantly. An enemy standing just past the edge of your new tunnel still took the full hit, and so did you if you were the same distance away on the other side.

A lit stick vanishes if you leave the world before the fuse runs out. That is the emergency brake when one lands next to your chest room or a town NPC.