Crystron Citree is not being reprinted in Supreme Darkness, and since it has only been printed once (back in 2016), Speculators and forward-thinking players were quick to buy out this card when those details were revealed on August 6th
You have to wait a turn and connect with a card that a lot of removal will take down before you get life back

============ Main Deck : 41 ============ Maxx "C" x3 Spellbook Magician of Prophecy x1 Aleister the Invoker x3 Majesty Maiden, the True Dracomage x1 Dynamite Knuckle, the True Dracofighter x3 Master Peace, the True Dracoslaying King x1 Ghost Ash & Beautiful Spring x3 Ghost Ogre & Snow Rabbit x1 Spellbook of Secrets x2 Invocation x2 Terraforming x2 Harpie's Feather Duster x1 Spellbook of Galdrabook x1 Cosmic Cyclone x2 True Draco Succession x3 Dragonic Diagram x1 Magical Meltdown x2 Ethereal Wyrmterfall x2 Revival of the True King x3 Apocalypse of the True Dracos x3 ============ Extra Deck : 15 ============ Invoked Magellanica x1 Invoked Caliga x2 Invoked Raidjin x2 Invoked Cocytus x1 Invoked Purgatrio x2 Invoked Mechaba x2 Invoked Elysium x1 Abyss Dweller x1 Castel, the Skyblaster Musketeer x1 No.41 Baguska Evilswarm Exciton Knight x1 ============ Side Deck : 15 ============ Skull Meister x3 Artifact Lancea x2 System Down x3 Dark Hole x2 Different Dimension Ground x2 Heavy Dust Storm x2 Vanity's Emptiness x1 A Spellbook engine is used to boost draw power of the deck

Additionally, here's some of the criteria I'm looking for when it comes to pulling these cards
With these shortcomings in mind, I generally reserve Beseech the Queen for 1-2 color decks, or any deck that can consistently access Urborg, Tomb of Yawgmoth early in the game