Drawing a card whenever you cast a spell with mana value 5 or greater is excellent with sweepers like pre-rotation Sunfall, where you can kill every creature and draw a card, with removal spells like Leyline Binding, or with the various Overlords that can enter the battlefield for cheap via impeding, like Overlord of the Hauntwoods
You want to quest with this beefy character since he generates four lore each time
Not only does he easily slot in alongside YP in many of the same lists, he is a more robust stand-alone threat than YP is
With a little practice, these checks become second nature
Elder Dragon because you have to choose a Legendary leader for your deck (such as the Elder Dragon Legends from the original Legends expansion)
The Wizards Play Network version of the Mystery Booster contains a foil card, pulled from a curated list spanning over forty Magic sets