Foundations Drake Hatcher is a Blue mana Magic card
are trashing cards, which will be useful to you throughout the game as some of your cards are tied to the number of trashed cards
Agrus Kos triggers, so pay 1R/W to copy Soulbright Flamekins ability for each other creature we control
Both are also four-drops and they'll get any Swamp, even a dual land, but this is key in Black decks alongside Cabal Coffers and Cabal Stronghold and similar massive ramping from your Swamp count
I love the idea of being able to circumvent the disadvantage of Aggressive Mining or elongate Constant Mists hold on a game, but I never bought into the hype that makes Windgrace the second most popular Jund general
As for booster draft, some enemy decks are too fast and aggressive for cards like this, so the player must be prepared to side out Virtue of Persistence if need be