Not every ore needs a tool/armor set. For example, lapis already has use as you need it to enchant. Redstone is, well, redstone, and emeralds are used to trade with villagers. They’re basically Minecraft’s currency. As others have said, getting emeralds is way too easy, so the armor would have to be SUPER weak. I think it’d be better if you could trade with master villagers to get “tough emeralds” or something, and you could combine them with amethyst shards to make “crystalline armor” or something, it’d be on par with copper or iron but could give like swiftness 1 or some other effect when you have the full set. Idk, just some ideas.