Mythril Anvil

The moment you smelt your first Hardmode bars you hit a wall. The anvil you have used since day one cannot work them, and one of these two is the only fix. It belongs near the top of your list once the Wall of Flesh is down, because almost everything downstream waits behind it: the ore armor sets, the weapons made from those same bars, the tools that let you mine the next ore, and most wings.

The Mythril and Orichalcum versions do the same job and share the same recipe list, and any given world generates only one of the two ores, so the choice is usually made for you. Build whichever your world offers and do not go hunting the other.

There is also no reason to keep the old Iron or Lead Anvil around once this is placed. It inherits everything the basic anvil could make, so a single station covers both halves of the game. Put it in reach of your furnace and your other crafting stations, since plenty of Hardmode recipes want several in range at once.

Its reach stops at the Ancient Manipulator. Lunar material from the pillars and everything built out of it needs that station instead. So this anvil covers the long middle of a playthrough, from the first Hardmode ore all the way to the end of the pre-Lunar tiers, and then hands the job over for the final stretch.