As is, I dont think this card offers nearly enough utility to make it the best choice to build around, especially at 4 mana
The release of Scarlet and Violet, the latest TCG set in March 2023, meant there are now 95 English main sets and 88 Japanese sets
Even in Standard, I can see Mirror Room finding a home using various blue strategies
Some were originally shown as P1 in promotional images, but the Challenge promo cards from Season 1 used the C1 set label
Cardsphere is safer than eBay because it flags buyers that have attempted to send cards back or claim that a card is fake when it isnt
The issue, however, is that Molderhulk is very difficult to get down too early since you need to spend resources to get lands into your graveyard