I was a Wizards of the Coast Great Designer Search 3 candidate, and got only two questions wrong on the test
Sephiroth, the Savior (Atraxa, Grand Unifier) Rating: 8/10 Seven mana over four colors is a big ask, but Atraxa, Grand Unifier is unbelievably powerful
In Magic: The Gathering, tutors are a special type of card that let you fetch up another card of your choice out of your deck
You can't put a Teferi's Moat out there for a long, long time against decks unknown with the knowledge that an enchantment removal or bounce spell will almost certainly kill you unless you are very brave, and once you start down the Moat road it's hard to stop
For example, Borrowed Malevolence with both modes chosen costs to cast if you control Voracious Reader
You should not run these without good reason