My idea is for there to be more variety on the distribution, generation and rarity of the different types of ores.
This already kind of exists in Badlands biomes where Gold Ore is common near the surface or in Mountain biomes which is the only place where Emerald Ore can be found. These biomes are some of the most fun and sought-after to mine in due to these reasons, so why not take it a step further and apply this to more biomes? This will give more reason to mine in certain biomes for a certain type of ore.
For example, want more Iron Ore? Maybe Iron Ore is more common in Savanna biomes.
While some ore types could be more common in certain biomes, at the same time, some different ore types could be less common in these biomes, although not so much such that it makes starting a new world in these biomes too difficult of course. For example, if Iron Ore is more common in Savanna biomes, maybe Coal and Gold Ore should become less common than what they are in Savanna biomes. But not so much such that it becomes too difficult to obtain these ores for a new player who is starting out in a Savanna biome.
Here is a full list of every biome and some ideas of how I think ore rarity could be different in these biomes to make mining more dynamic. Of course, these ideas can be tweaked.
Forest, Birch Forest, Plains, Taiga, Snowy Taiga: Stays the same
Roofed Forest, Swamp: More Coal at layer 32 and above. However, all other ores all decrease very slightly.
Desert: More Iron. Decreased Diamonds, Lapis Lazuli and Redstone.
Badlands: As current, lots of extra Gold at 32-79. To balance this perhaps Coal and Iron should be greatly reduced, and Diamonds and Lapis Lazuli also slightly reduced.
Savanna: Can generate with Iron on all levels (so also above layer 64 up to 256, but still at the same rarity). This would make mining into Shattered Savannas worthwhile (I've always thought those giant mountains and plateaus that can generate look so cool and the ability to mine into them for Iron could provide a neat challenge). To balance this, Coal and Gold should be reduced.
Jungle: Increased Coal. Diamond is slightly more common too and can generate up to layer 24 Also why not add Emerald ore to a few other biomes besides Mountains? Iron, Gold, Lapis Lazuli and Redstone is reduced.
Mountains: As current, Emerald Ore can be found up to layer 32. Redstone and Lapis Lazuli can be found above layer 80 to encourage mining into mountains above ground level (but they are slightly rarer than what they are underground)
Giant Tree Taiga: Redstone can be found in slightly larger quantities and up to layer 32. Reduced Lapis Lazuli and Gold.
Snowy Tundra: Lapis Lazuli can be found up to layer 64, being more common between 24-40. Reduced Redstone and Gold.
Regular, Cold and Frozen Oceans: Lapis Lazuli, Diamonds and Emeralds can be found up to layer 40 (although diamonds are half as common above 16).
Warm and Lukewarm Oceans: Redstone, Gold and Emeralds are found up to layer 40.
(Note: I don't think any ores should be decreased in ocean biomes since mining in ocean biomes is pretty difficult due to it being underwater and due to a lot of caves being filled with water. Hence just having ores increased in these biomes will encourage underwater mining)
I agree but I also feel it would be great to have more ores like copper, silver, aluminum, cobalt, etc. included just so there’s more variety and more common metals than iron, maybe metal like cobalt could be valuable, while aluminum is as common as coal
I support this idea. Having a config to switch between standard distribution and biome specific distribution would be good. A config to specify the biome specific amounts wouldn't go a miss for servers either.
It is likely that you will be able to change ores per biome when they bring back Customized worlds; I once decompiled 1.13 and instead of using a single class to generate all decorations, including most ores, each biome defined the ores that it has separately (they were all the same, aside from Extreme Hills and Mesa, as before), and even things like caves and structures (unfortunately, only the "chance" was coded in as a parameter to the generators, so no 1.6.4-type caves yet):
This is a list of all the classes that had the value "0.142857", which is used as the chance of cave systems since 1.13 (previous versions back to 1.7 used "nextInt(7) == 0" to determine if caves should generate, giving the same chance; 1.6.4 and before used "nextInt(15) == 0", or about half the chance, offset but a much larger "size" value, still hardcoded into the cave generator), the line right after has the chance of ravines (0.02 or previously "nextInt(50) == 0"), and the line before mineshafts (0.004, or 0.01 for 1.6.4 and before):
The list of ores as seen in the first class listed, recognizable because of the numbers used, matching the values for 1.12.2 and earlier (the last line matches the additional gold that generates above layer 32 in mesas so this was a class for a variant of that biome, most others did not have it). Given the contents of all of these classes they were very likely the classes that define the characteristics of each individual biome (older versions had a single class that generated most normal ores and most decorations, with the amounts of some able to be varied, with caves and structures defined in another single class):