In a normal set, maybe one card would see a price increase, but if Merfolk succeed in Standard, a whole bunch of cards from Rivals of Ixalan will be in demand, including Merfolk Mistbinder, Silvergill Adept, Kumena, Tyrant of Orazca, and perhaps something like Jadelight Ranger or Hadana's Climb as well
Putting tons of Goblins into play as rapidly as possible suits Foundry Street Denizen perfectly, and its ability makes it an important creature that will always requires a blocker
You can only Special Summon Dark Magician of Destruction once per turn this way, no matter which method you use
We inspect edge whitening, corner wear, and surface marks
Do you expect any specific characters, monsters, or other aspects of the series to make an appearance