If there are no creatures to receive the Last of the Abzans bounty, all our hard work is for naught
Sword of Feast and Famine is definitely a favorite, too: The moody sky, the glowing moon, and the fact that you can untap all of your lands by dealing damage to an equipped creature make it viable just about anywhere
Madness is such a strong effect as it turns discarding, something that can be a downside, into extra value with a discounted spell
Suspend cards often have lower costs to suspend then they would otherwise have through their regular casting costs to balance the downside of waiting to cast it
Then theres initiative, which is an addition to the venture/dungeon mechanic that allows you to venture into the Undercity during your upkeep when you have it
Infinite tokens lets you activate Baylens abilities as much as you want