Alongside Zapdos & Moltres, Articuno was given away in the first few weeks of the theatrical release of Pokémon the Movie 2000: The Power of One! It is one of the many Black Star Promos released by Wizards of the Coast.
2000 Wizards Black Star Promo Articuno
@PokemonCenturyadded December 20, 2019
Wizards Of The Coast