RELEASING SOON
That's because one (with art by Andreas Rocha depicting a waterfall of lava dumping into a mountain stream) is from the actual expansion set Dragons of Tarkir, while the other (with art by Noah Bradley depicting a river of lava winding towards an oasis) is one of the possible prizes from the Dragonfury Promo, a dexterity-based dice throwing game available at select Dragons of Tarkir prerelease events
He encourages you to build your deck with a lot of mana value 3 or less creatures, and gives you a mini-Winota style effect
These colors do work well with instants and sorceries, in-line with Gandalf's spellcasting theme, but it would've been better in white mana with related effects to please dedicated LotR fans cracking Tales of Middle-earth Boosters
Lords are always among the strongest creatures for tribes, offering team wide power and toughness boosts
You only have to look at the fact that we got a reprint of Heroes Downfall, one of the best pieces of removal in Standard history, but downshifted from rare to uncommon, to see how much Magic has changed