I have an Ankylosaurus at Herbivore Island that I use for metal mining. Since this is coming from ARK Mobile, the metal rocks resplendent rather quickly. Because of all of this, I have 500+ metal ingots stored up in my smithy, ready to be used for something late-game. Tame an Ankylosaurus at Herbivore Island, they will get you all of the metal. Just make sure your Ankylosaurus has good weight for maximum efficiency.