Loot tables per item/tier?

[hollow fox]

I want stone/cobble blocks to drop 1-2 pebble items (from a mod) when mined with stone tools, but drop normal cobblestone with higher tiers. Best way to do that?
Also maybe make logs only drop when using an axe

[tulip junco]

Once your ticket has been resolved, please close it with </ticket close:1054771505520717835> command!

[broken imp]

I had to do something similar found this thread while browsing https://github.com/KubeJS-Mods/KubeJS/issues/189

For needing a specific tool tier the easiest way is to use block tags (server_scripts):

ServerEvents.tags('block', event => {
  // Remove blocks from their current tier
  event.remove('minecraft:needs_iron_tool', 'minecraft:diamond_block');

  // Force blocks to be mined with netherite tool to drop item
  event.add('neoforge:needs_netherite_tool', 'minecraft:diamond_block');
})

For requiring a tool you can use a block event modification (startup script):

BlockEvents.modification(event => {
  // Make blocks requiring to be broken by a tool for the item to drop 
  event.modify('minecraft:wither_skeleton_skull', block => {
    block.requiresTool = true;
  });
});

For your pebble things it gets more tricky, one way is to manually modify the loot tables using the LootJS addon.
If you want some examples of what a block loot table looks like to figure out how to implement your own a nice ressource is https://misode.github.io/loot-table here is the entry for the brown mushroom block which has a kinda similar behavior https://misode.github.io/loot-table/?version=1.21&preset=blocks/brown_mushroom_block
You may need to change the block event or some tags of your block as well to make this work.

Here is an example lootJS script I made to recreate the loot tables of some ores which didn't work properly inside my modpack.

LootJS.lootTables(event => {
  const rawOres = ['copper', 'iron', 'gold'];

  function createOreTable(block, item, lootTable) {
    if (lootTable == undefined) {
        lootTable = block.replace(':', ':blocks/');
    }
    event.getLootTable(lootTable).firstPool(pool => {
      pool.addEntry(
        LootEntry.alternative(
          // loot block when using silk touch
          LootEntry.of(block).when(c => 
            c.matchTool(
              ItemFilter.tag("c:tools").and(ItemFilter.hasEnchantment("minecraft:silk_touch"))
            )
          ),
          // loot item otherwise
          LootEntry.of(item).applyOreBonus("minecraft:fortune")
        )
      )
    })
  }

  // Remove bugged loot tables
  event.clearLootTables(/.*blocks\/(deepslate_)?diamond_ore.*/);
  event.clearLootTables(/.*blocks\/(deepslate_)?(copper|iron|gold)_ore.*/);
  
  // Create new loot tables
  createOreTable('minecraft:diamond_ore', 'hardmodeores:diamond_shard');
  createOreTable('minecraft:deepslate_diamond_ore', 'hardmodeores:diamond_shard');
  rawOres.forEach(m => {
    createOreTable('minecraft:' + m + '_ore', 'minecraft:raw_' + m);
    createOreTable('minecraft:deepslate_' + m + '_ore', 'minecraft:raw_' + m);
  });
})