Some cave biomes have more of a certain ore/stone than others

This would add a lot of strategy to mining like LadyAgnes said on Minecraft Live 2020. Lush caves, since they are so full of life, would have more coal. The deep dark, because of all the pressure, would have more diamonds. The dripstone caves, would have more gravel, which is a source of flint, and would also potentially have more archeological exacavations because of the presence of sedimentary rocks. A new Lava/Basalt cave biome would be cool, where it would be home to more igneous rocks such as Andestite, Diorite, Granite, and Tuff. Maybe in the extreme hills biome, Emerald Ore would generate more times in patches of Granite, as they do in real life. I just think adding stuff like this would add a lot more strategy for mining, because if one needed diamonds, they would visit the deep dark biome, but if they just wanted coal to power their super-smelter, the Lush Caves would be the place to visit.