Cryptic: Marneus Augustus Calgar is a veteran of countless battles, including one against The Swarmlord, and later one encounter with Abaddon where he technically died before being restored as a Primaris Astartes, lieutenant of the acting Regent of the Imperium of Man
That alone makes it awkward to play around
Which is all to say, the pull rates suck compared to those of previous Mega Evolutions sets, rights when we needed them not to the most
Some involve an imbalanced resource conversion, like [casthaven]Ancient Tomb[/casthaven] (two life is absolutely worth an extra mana), others rely on a resource strong enough to easily build a deck around, such as [casthaven]Tolarian Academy[/casthaven] and [casthaven]Mishras Workshop[/casthaven]
Draw Extra Cards: In contrast to the main TCG, card draw is a lot less widely available, but still present: Professor's Research allows the player to draw two extra cards