The vast majority of the cards in Mono-Blue are common or uncommon, and it is very easy to accumulate the necessary wild cards to craft cards of that rarity on Magic Arena
In Bloomburrow, the Valley is threatened by elemental forces raging out of control, and salvation falls on the shoulders of its smallest protectors
Butcher of the Horde and Chandra get along fine, but the card that was really overperforming was Crackling Doom
Collectors, on the other hand, could be choosing to chase this card down due to their love of the song or, more generally, the music of Mulan
But for a 5-mana commander, Id prefer a card that stands on its own and doesnt require other cards to do things after it enters
You can play this black ramp piece in other color combinations thanks to Urborg, Tomb of Yawgmoth, but those decks make this black land a weak half of a 2-card combo