Iron

Inside a chest with a medium-difficulty lock. One of the Cumans in the camp holds the key.

3 are inside a stash in the Thieves’ camp.

Inside a chest with a medium-difficulty lock. The thief in the camp has the key.

4 are inside a chest with a medium-difficulty lock in the ruined house.

Inside a closet in the room with a very-hard-to-pick lock on the door, near the kitchens.

3 are inside a chest with a medium-difficulty lock on the upper floor of a building that acts as the Deserters’ camp.

Found in a medium-difficulty chest in an underground tunnel beneath Burnt Mezholes. You can find the entrance next to the large burned down building east of the map marker.

Credit to GG user Storm Cell for finding the tunne!