Spelunker

A type of villager that would spawn in the caves. The mob could give cave related items, like Raw Ores and amethyst. Maybe even a bundle? The mob would have two unique items that it could give you, and that's the Spelunking Potion. This potion when used would cause all ores within a 300 block radius to start glowing for 10 - 15 seconds. The second item would be the Crystalline Compass. It would cost more emeralds than the other items you can get from the Spelunker. The compass would be composed of Amethyst. If you give the compass one amethyst shard, it will lead you to any random structure, such as a Mob Dungeon, Mineshaft, Village and other structures. If you give it two shards, it will lead you to structures with more loot, but will have a rare chance to lead you to a Giant Ore Vein. This would just be a fun addition to the new caves.