Pickaxes are the core mining tool — each has a pickaxe power rating that sets which ores it can break. Work up the tier ladder from Copper to the Lunar pickaxes, and beat the Mechanical Bosses to reach the power needed for Hardmode ores. Drills are the continuous-mining alternative.
The Lunar pickaxes — Solar Flare, Vortex, Nebula and Stardust — have the highest pickaxe power and mine every block in the game. Before the Moon Lord, the Picksaw and Chlorophyte-tier tools lead.
Copper/Tin, Iron/Lead, Silver/Tungsten, Gold/Platinum, then Nightmare/Deathbringer and Molten. Hardmode adds Cobalt/Palladium, Mythril/Orichalcum, Adamantite/Titanium, the Pickaxe Axe and Drax, then Chlorophyte, Spectre and finally the Luminite pickaxes.