Minecraft wiki entry for Luck, associated text: 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 generic.luck 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.
Bedrock Edition has unused textures for Luck potions, despite the fact that Luck is not present in said edition.