Of the existing cards, Jackdaw looks like the biggest benefactor
"Discover," as it's helpfully called, is a lot like Cascade--it lets you dig through your deck to play cards that you'd otherwise have to wait for
Thunder Totem It could be better, but Thunder Totem can act as a mana rock that can later become a creature
From a design standpoint, if your opponent is able to kill it before it can attack, it's essentially the same as it having pseudo-haste and dealing seven damage
Players will be able to build and utilise their own decks against Ursula, who will have four different modes of difficulty, from easy to extreme, for up to four players to challenge
I also like how well this works with ability counters and shield counters, adding a touch more diversity to the deck