He asks your opponent to have something very specific, like a "target opponent sacrifices" effect, a board wipe that gets around Regenerate, and/or a way to shrink him through toughness reduction
10: Jason Chan ( Jason Chan has worked on some of Magics most powerful cards in recent times such as Avacyn, Angel of Hope and Jace, the Mind Sculptor as well as cards like both versions of Xenagos and Deicide above
In other words, all the Foundations cards (except Jumpstart) are going to be a part of the format for the foreseeable future
The commander, Teval, the Balanced Scale, creates a loop of sacrificing and reanimating that feels inevitable in long games
It's important to note that not every card is suitable for grading, so carefully consider which cards justify the effort and cost.