Six caves in your deck gives you a 70% chance of seeing at least two by the time you cast this, and thats not taking into account other draw spells or self-mill
Here are the cards Im most often seeing players misevaluate and where my ranking of them stands comparatively
"The Treasure Test"
You cast cards like Sire of Seven Deaths, Hideous Taskmaster, Flayer of Loyalties, or Emrakul, the World Anew, as well as the different versions of Kozilek and Ulamog
This sees play in all formats that its legal in, from Cycling Storm in Pauper to Living End and Deaths Shadow in Modern to Doomsday in Vintage
All of these actions triggering without requiring combat is extremely effective, and when paired with other ways to boost the power and toughness of creatures, all while backup Commander Director Nick Fury is reducing the cost of Heroes by 1C, you can see why this deck is being hyped up as powerful right out of the box