0306_MTGM19_Promo_Buy-a-Box: Nexus of Fate Included in Mystery Booster 2 are a handful of vanilla creatures in the set that appear with their non-English printings
Any ability that triggers whenever you draw a card, for example, will trigger
Unlike many ramp effects, it can grab any Forest, not just Basic ones - allowing it to dig up certain dual- and tri-lands - and still leaves behind a creature, albeit a small one
What you plan to ultimately use that mana for is, as usual, less important than working out how to harness the Cobra as effectively and reliably as possible
Decks like Dredge and Hogaak have a very difficult time beating Leyline of the Void when it sits in play
But the main reason for building so many decks is a simple one