Our creatures start off as 4/4's and 5/5's (Lambholt Elder) and only get bigger thanks to our lords (Mayor of Avabruck), which put them in a prime position to start mauling opposing creatures
In the game, Elsa costs 8 Ink (or 6 using Shift, placing her on top of another Elsa card), and has 4 Strength, 6 Willpower, and 3 Lore
Ramp : Ramp decks want to build enough mana to cast powerful cards that are too much for opponents to deal with
Another very high contender for the most expensive cards in Unlimited is Chaos Orb
Giving all your dragons indestructible means you can swing and block without fear, and the bonus of stacking +1/+1 counters every upkeep quickly snowballs, all on top of a potential alternate win condition
One thing that's interesting, and worth considering, is whether The Deck of Many Things is actually any better in a Mr House deck than in other dice-rolling commanders like Wyll or Farideh, Devil's Chosen