Blacks Crystal offers some rather unique effects that could go in a variety of different decks, but unlike some of the other Crystals, this doesnt really create any exponential value
Since the original card could be worth a lot in value (or sentimental value) many owners will make a proxy card and use that to preserve the original
On the other side, Jund Midrange combines the formats most powerful standalone cards, such as Familiar, Writhing Chrysalis, and Cleansing Wildfire, with the best card advantage engine (Deadly Dispute plus Ichor Wellspring), and a solid suite of removal spells
Black's two enchantments, Nether Void and The Abyss , have pretty cool and atmospheric artwork that do really look like very nice painting
Thoughtseize is the spell that most players first think of when asked about discard spells, as it's capable of discarding any single card you want from your opponent's hand