Anything with the ability to improve consistency and set up players for a counter when going second is good, but if your opponent has built up quite the impenetrable field with nine or more cards on their field when excavating from the deck, your opponent must shuffle their entire field and Graveyard in the End Phase
1 Starmie ex Free Retreat Starmie has a very similar attack to Pikachu with the added consistency that it doesnt need Benched Pokemon to reach max power
Add another 4 floors full of pokmon goodies, buying stations, and a tournament area, and youve got Hareruya2, the 6-floor behemoth located just seconds away from the station
Along with the above requirements, some Pokemon, such as Raikou V, have a draw Ability like Fleet Footed that requires the Pokemon to be in the Active Spot to use their Ability
When a monster would be Special Summoned, OR when a card or effect is activated (Quick Effect): You can negate the Summon OR activation, and if you do, destroy that card