Pokemon Sword and Shield have been available on consoles for over a week now and players are still discovering the mysteries of the Wild Area.
The Pokemon Sword and Shield Wild Area is populated with "Raid Dens", gray and red glowing hexagonal structures that can hold powerful Raid Pokemon. These Pokemon come with guaranteed maximum IVs, and sometimes have hidden abilities that can be very powerful.
DISCLAIMER: When you're using this method, please be sure to have your Internet connectivity turned off. Players will be bombarded by empty stamps if you do this while connected! Once you've found a raid you're happy with, reconnect and play with others online!
The Pokemon that spawn during these raids are pulled from a specific group, and that group is determined by which color of the beam of light is when it's spawned. (You can find the list here at Serebii.)These raid lights can either be red or bright purple, which are the common or the rare raid pools respectively. Generally, these raids are scattered around the map daily and refresh once all of them are cleared. However, a Wishing Star can be used in order to spawn a raid Pokemon manually.
Using these Wishing Piece, it is actually possible to control which beam of light comes out of the den, allowing a modicum of control over the system.
Here are the steps: