Iron

Roof of the house.

Near end of high ground.

In a pit.

Near Tera Golduck.

Rocky ledge.

Shallow water.

High ground.

Next to a mound.

On island with Eelektross tera.

Nestled next to a large rock mound in Tagtree Thicket.
Note: Items will respawn after the first instance within a random pool of items.

On the southern tip of the middle island in West Paldean Sea, just off the coast of the Asado Desert.

Inside Torchlit Labyrinth.

Inside Chargestone Cavern, lower level.