Luck

Luck is a status effect that makes it more likely to receive better loot from certain loot tables, contrary to.

Effect
Adds 1 × level to attribute, making loot table entries with a high   score more likely, and entries with negative   less likely. It also increases the chances of  occurring. Currently, only fishing uses. The new weight of each entry is. Negative levels decrease luck.

Immune mobs
While no mobs, except bosses, are immune to Luck, only players are actually affected.

Trivia

 * The potion for Luck is unobtainable in survival without the use of cheats.
 * Using a fishing rod enchanted with Luck of the Sea increases a player's  attribute, but doesn't actually grant the Luck status effect.
 * Contrary to real-life superstition, a rabbit's foot has no effect on luck in the game.
 * The fact that the icon for Luck is a four-leaf clover, or a shamrock in Irish (though this one only has three) is a reference to how seeing one can make you lucky in real-life superstition.
 * Bedrock Edition has unused textures for Luck potions, despite the fact that Luck is not present in said edition.