What I think should be added is extremely rare ores from mythology and rare and hard metals from real life. The Mythical ores would consist of Adamantite, Mithril, and Orichalcum. Real Life metals would consist of Cobalt, Platinum, Titanium, Copper, and Silver. Rubies would be added as a material and Armor and tools/weapons made from them would have slightly less durability than diamond since ruby is the second hardest gem in the world. Also, Emerald Armor/tools/weapons should be added too to give Emeralds more use than money. The mythical metals would be extremely rare because of how strong they are, like how Orichalcum is nearly indestructible. Along with the current metals in minecraft, the real life metals' rarity would be determined by their strength. Copper would be the most common, sliver would be more common than gold but less common than Iron, Titanium would be more common than Platinum but less common than Gold, and Platinum would be less common than Diamonds. Rubies would be more common than Diamonds but less common than Platinum and they only appear in the same layers as diamonds. Adamantite would only be found in Epic Hills biomes, Mithril would only be found in ocean Biomes, and Orichalcum would only be found in Mushroom biomes because it is the strongest of the three and because Mushroom biomes are very rare.

The reason I would want this is because it would add more of a variety of weapons and Armor and I would love to make a "Legendary" Sword out of a Mythical Metal. And the Ruby is just gathering dust in Minecraft so we might as well give it a use. Also, it would be nice to have more uses for Emeralds. And finally, it would be nice to have achievements for finding the Mythical Metals.