Baral, Chief of Compliance and Archmage of Runes are premier counterspell payoffs
Sauron's "enter the battlefield" effect is a classic Threaten effect, taking control of an opponent's creature, untapping it, and giving it haste until end of turn
Currently, people are underestimating the value of starting with an extra card in hand each game, but with the set being released shortly, I expect people will wake up to the mechanic's absurd power soon
If your Commander is Akroma, Angel of Fury, you may cast her face down from the command zone
I expect people to try this alongside Craterhoof Behemoth in Standard, and you better believe itll show up in EDH, at minimum in every Kinnan, Bonder Prodigy deck out there, and many more places, too
(It can't be blocked except by two or more creatures.) If you controlled a creature with power 4 or greater when you declared Courageous Goblin as an attacker, it doesn't matter whether you still control one as its ability resolves