Universal Pylon

Filling the bestiary to completion means every fish caught, every critter netted, every enemy killed at least once, including the ones locked behind seasonal events and rare spawns. It is a long side project and this is what waits at the end of it. By the time you finish, the game is over, so treat it as a comfort item rather than a goal to rush.

One per world, it works anywhere, and nothing has to live next to it. That last part is what makes it useful, because the areas without a pylon of their own are exactly the areas nobody can be housed in: the Dungeon, the Jungle Temple, the evil biome, and space. Put it wherever you keep walking back to.

Since you can pick it up and set it down again, it works as a portable anchor. Drop it where you are digging, jump home through a pylon in your base to empty your inventory, then jump straight back to the hole you were in. It is a Potion of Return you never have to brew again.