You may reveal a creature or land card from among them and put it into your hand

Acererak the Archlich Aphemia, the Cacophony Archdemon of Unx Assemble the Rank and Vile Bone Miser Boneclad Necromancer Bridge from Below Cellar Door Cemetery Reaper Corpse Cobble Cradle of the Accursed Crowded Crypt Cryptbreaker Curse of Disturbance Curse of Shallow Graves Curse of the Restless Dead Death Tyrant Deluge of the Dead Diregraf Colossus Doomed Dissenter Drana's Chosen Dread Summons Drunau Corpse Trawler Dunes of the Dead Dying to Serve Embalmed Ascendant Falcon Abomination Feast or Famine Field of the Dead Flip the Switch Ghoulcaller's Accomplice Ghoulish Procession Graf Harvest Gravedig Graveyard Marshal Grim Reaper's Scythe Grixis Slavedriver Havengul Runebinder Headless Rider Hildibrand Manderville Hildibrand Manderville Hobbling Zombie Hour of Victory Jadar, Ghoulcaller of Nephalia Kalitas, Traitor of Ghet Lair of the Ashen Idol Liliana's Devotee Liliana's Reaver Liliana, Death's Majesty Liliana, Dreadhorde General Liliana, Heretical Healer Magus of the Bridge Midnight Ritual Necromancer's Covenant Necromancer's Stockpile Necromaster Dragon Necromentia Nested Ghoul Never // Return Never // Return Nevinyrral, Urborg Tyrant No Way Out Noosegraf Mob Null Caller Oath of Liliana Oglor, Devoted Assistant Open the Graves Overseer of the Damned Poppet Stitcher Rank Officer Reap the Seagraf Revenge of the Drowned

When the last is removed, you may cast it without paying its mana cost.) Illustrated by Matt Cavotta Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Legal Brawl Not Legal Legacy Legal Comp
Although it is a risky play, as phasing your creatures out leaves you totally open to attack, in many situations, its part of the reason why cards like Teferis Protection and Guardian of Faith see so much play