When you mill your opponent, there's no real guarantee what you're going to hit
These can be found on the home screen under the booster packs on the left side
It's a small distinction, mind you, but it does make all the difference
As far as being at the front of a deck, there may be better choice but I think there might be a few of these out in the wild for a number of years
Ayara, Widow of the Realm is a sacrifice outlet that rewards you for sacrificing expensive Creatures or Artifacts by damaging an opponent and healing you, equal to the Mana Value of the sacrificed card
Gornog, the Red Reaper was first released in the set Foundations Jumpstart, illustrated by Ishikawa Kenta