If you still have a couple of empty spots in your Pokémon Sword/Shield Pokédex, now is a good time to sort that out, as a new event has started. This time, the Wild Area in the game has shifted so Sword is now Shield, and Shield is Sword. That means you can now catch pokémons that was previously unavailable in your version of the game.
The "Pokedex Completion Event" (that's the actual name) lasts until March 25. If you are on Shield, take the opportunity to catch creatures like Machamp and Farfetch'd and if you're a Sword owners make sure to catch Ponyta and Lapras among others.