Everything in the Eldrazi Unbound Commander deck: all 100 cards with current prices, what the deck is worth against the sealed price, the 10 new cards, and whether it is worth buying.
Colorless spells you cast from your hand with mana value 7 or greater have "Cascade, cascade." (When you cast one, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Then do it again.)
Eldrazi Unbound could have done with a different deck name, since it set the expectation of a fully-focused Eldrazi precon but only half committed to the theme. The deck itself is great, with one of the most impressive rosters of new cards I’ve ever seen in a precon. The “wow factor” of a completely colorless precon works for me, and it should give you plenty of useful tools, new and old, for your collection.
Eldrazi Unbound is another innovative Commander deck since it’s the first ever fully colorless precon. The name is a bit misleading though. While it features new and familiar Eldrazi cards, it’s actually only half dedicated to Eldrazi, with the other half containing generic artifact support. That’s to be expected, but the themes are split down the middle. For reference, imagine if the Sliver Swarm precon were half slivers, half zombies or something along those lines.
To drive home this point, only one of the two new legendary creatures is an Eldrazi. Zhulodok, Void Gorger is the face commander, and one of only two new Eldrazi creatures in the deck. The alternate commander is Omarthis, Ghostfire Initiate, a commander focused on the manifest mechanic. Even though it’s cool in its own right, it has no inherent Eldrazi synergies at all. They’re both intriguing new colorless legends, but they highlight the somewhat misleading deck title.
The out-of-the-box strategy is exactly what you’d expect from a completely colorless Commander deck: a heavy emphasis on artifact ramp, top-end threats, and utility lands to round out an unrestrictive mana base. However, you could always upgrade the deck!