You can retrieve any basic land, so whether you need Wastes for Eldrazi, a color of mana you dont have access to in multicolored decks, or more Forests (in which case, also consider Nissas Pilgrimage), Kodamas Reach and Cultivate are great cards for helping you accelerate into the midgame
Its actually a 0-mana saga that behaves as a land by generating mana
This mechanism prevents old-school veteran players from making extremely powerful decks from cards that they acquired over a decade
Things that you occasionally hear whispers about from crazy collectors but can't really confirm (or perhaps don't want look for confirmation to, as the whispers are a part of the Magic)
Basically if the original card is legal, the promo is also okay to be played in that format
Auras attached to the exiled creatures will be put into their owners' graveyards