amaniku
Terrarian
The Ancient Chisel is a great QoL addition, so much so that it should be tinkered to avoid taking a dedicated slot (see also here). Since mining speed is more of a concern in Pre-Hardmode, here are a couple of combos with other Pre-HM accessories:
Amphibian Chisel
(via Frog Leg)
Being able to dig both higher and faster really improves cavern exploration, especially when excavating the ceiling.
Obsidian Chisel
(via Obsidian Skull)
I almost expected this to already exist, since it speeds up the collection of Meteorite (which is time-consuming) and Hellstone (which is dangerous).
(via Frog Leg)
(via Obsidian Skull)