One of the many benefits to trading Pokémon with friends is that you have a chance at receiving a Lucky Pokémon. Lucky Pokémon are more likely to be strong opponents in battle, require less Stardust to power up, and appear with a shimmery effect in the Pokédex and on the Pokémon's Summary page.

Although Pokémon turn into Lucky Pokémon at random when traded, the longer you have a Pokémon, the greater the chances that they will become Lucky Pokémon.