Pumpkin/assets/datapack/data/minecraft/loot_table/entities/sheep/yellow.json

{
  "type": "minecraft:entity",
  "pools": [
    {
      "entries": [
        {
          "type": "minecraft:item",
          "name": "minecraft:yellow_wool"
        }
      ],
      "rolls": 1
    }
  ],
  "random_sequence": "minecraft:entities/sheep/yellow"
}