Compass

Knowing how far east or west you are sounds trivial until you are digging a long tunnel or trying to walk back to a spot you never marked. Zero sits essentially at your spawn, so every reading is a distance from home rather than an abstract coordinate.

Anything you want centered on the world, or two structures you want at matching distances from spawn, is guesswork without one. Worth knowing if you care about precision: the center reading covers two columns of tiles rather than one, so the true middle of the world is the seam between them.

It does not need an accessory slot, and teammates standing near you get the same readout for free. Getting one means killing a lot of crawdads, salamanders and vikings. Statue spawned enemies drop it at a small fraction of the natural rate, so building a statue farm for it is the slow road, not the shortcut.