Set 1 Call of the Haunted from your Deck or GY, and if you do, discard 1 card
Master Duel, so whilst you can find some truly overpowered cards, it's recommended that you just open packs, explore each one you unlock, and go with what sounds interesting.
UR Ultra Rare Performapal Swincobra X EARTH Level 4 [ ReptilePendulumEffect ] ATK 300 DEF 1800 P Scale 2 Once per turn, when a monster you control inflicts battle damage to your opponent: You can send the top card of your opponent's Deck to the Graveyard
You cannot declare attacks the turn you activate this card, except with EARTH Warrior monsters
Griggle
Finally, the Deck runs into the issue of running out of resources quickly due to the swapping effect Summoning from the Deck, which is only mitigated by the effect of "Phantasos, the Dream Mirror Friend"