Here’s some shipping crate resources you can utilize, if you want to use metal ones. These materials are meant to help you add to the ambience of darker environment areas. These were done for a small crystal mine location - the blue shards were collected into the metal shipping crates throughout the dungeon area.

They are then sent to a factory, where ancient magic & mineral resources are extracted from the crystal shards. There is not much shading on the metal, so only use the shipping crates with similar tilesets where they won’t stand out badly.