Really Lucky

With the mod installed on a server, Fortune applies its maximum effect when mining ores, so a diamond ore mined with Fortune 3 always yields four diamonds. Looting works the same way for mobs: a sword with Looting 2 always makes a creeper drop two extra gunpowder, instead of the default chance. The mod also changes the random range used for extra loot, so a range of 0 to 3 is used in place of the vanilla 0 to 5 and 2 to 5 values.

Rare mob drops such as potato zombie wither skulls and wither skeleton skulls become reachable with a fixed Looting level, and Looting 3 raises the rare drop chance for certain mobs to 33.4 percent. The Luck of the Sea enchantment is affected too, so a fishing rod with Luck of the Sea 3 reliably catches treasure. Fortune and Looting apply to modded ores and mobs as well, as long as they use the standard loot mechanics.

Only the server needs the mod, so players join without installing it. The mod is released under the MIT License and is open source, with source code published. Files exist for Fabric and NeoForge across 1.21.1 and the 26.x builds 26.1.2 and 26.3.