Question: what to do after beating champion sword and shield?
Answer: Get the Master Ball. What Pokémon game would be complete without this legendary 100 percent catch rate ball? ... 
Get the Beast Ball. Talk to the merchant at the right of Stow-on-Side to get a Beast Ball. ... 
Get Charmander. ... 
Get Type: Null. ... 
Learn Steel Beam. ... 
The Legendary Quest. ... 
Rare League Cards. ... 
The Battle Tower.