Because of that Pokemon anniversary event last year, I always had a reason to check in and pick up another free legendary. It was a pretty cool feeling and a neat way of keeping the game relevant even for casual players, and it looks like Nintendo and The Pokemon Company are bringing it back.
Starting in February, players can net legendary Pokemon each month. They'll come in pairs of two (and you'll need two copies to get them both), starting with Dialga and Palkia in February from Pokemon Pearl and Diamond at GameStop. It'll run until November, closing out with Ho-Oh and Lugia.
To clarify, this year's promotion will work with four versions of Pokemon -- Sun, Moon, Ultra Sun, and Ultra Moon. In other words if you have at least two copies of the game you can net both legendaries in any given month.
Legendary Pokemon Celebration [Pokemon]
via destructoid https://www.destructoid.com/nintendo-is-doing-that-awesome-legendary-a-month-giveaway-for-pokemon-again-this-year-483242.phtml