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
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.
In Advanced format, everyone is talking about how Vampires aren't good, but I like them from a thematic perspective
All of the normal Phantom Knight monsters are designed to be used as searchers and Xyz fodder
You cannot declare attacks the turn you activate this card, except with EARTH Warrior monsters
It also has the chance to be really weak, which is why it's last on this list