Power Nullifier: While normally you are limited to a single Supporter Card per turn, several Pokmon from Genetic Apex can prevent your opponent from activating them at all, such as by successfully resolving Psyduck's attack, or by having Gengar ex as your Active Pokmon
However, it is severe against Link Monsters, which cannot be used in Defense Position
Monarch Overview Monarch is a control deck that tries to gain and maintain both an advantageous board state and general card advantage using cards like Mobius the Frost Monarch and Zaborg the Thunder Monarch
It helps create a more refined presentation
If you are at all worried about total playables you are rarely going to pick a sideboard card over a main deck one
Otherwise, if youre not trying to get too fancy with your card designs, everythings fairly straightforward