Not only is the exact placing very subjective but there are a vast number of cards that seem rather hard done by to not be on this list including Sylvan Library, Joraga Treespeaker, Birthing Pod, Rofellos, Natural Order, Wall of Roots, Lotus Cobra and many more
Mishra, Tamer of Mak Fawa BPhillipYork: Mass handing out unearth is a scary powerful ability
Any time you attack with any creature, you can take an attacking Vampire you control and make it a Demon as well as being a Vampire
To anchor our discussion in practical Cube design, I use a thought experiment: if we assign a supercomputer 1 a set of design goals and restrictions, and then ask it to rank every possible Cube (i.e., every possible combination of 360 Magic cards 2 ) by power level tiers, it would look something like this: There are about 10 ways to combine the ~21,000 extant Magic cards into a 360 cube more possibilities than there are atoms in the universe, by a lot
Some type of threshold trigger (not graveyard)
But you can also just put it together