>>43443063Not Master balls. Each time you recomplete the Pokémon tournament, you have to fight against the RNG between giving you items your Pokémon may hold, or a random selection of standard or specialized uncommon pokeballs.
The only way you can get more masterballs is trying your luck in the Loto-ID. If the picked 5-digit number is exactly the same as one of your pokemons in the PC, you get a masterball, and the odds are so extremely low that many don’t consider it a worthwhile effort.