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
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
Baral, Chief of Compliance and Archmage of Runes are premier counterspell payoffs
They cant be interacted with at all, so they cant go anywhere else
Hope-Ender Coatl can be a surprise counterspell backed up by Ulaleks doubling abilities