Guilds of Ravnica

Blood Operative | Creature | Vampire Assassin | Lifelink When Blood Operative enters the battlefield, you may exile target card from a graveyard. Whenever you surveil, if Blood Operative is in your graveyard, you may pay 3 life. If you do, return Blood Operative to your hand. | Livia Prima

Midnight Reaper | Creature | Zombie Knight | Whenever a nontoken creature you control dies, Midnight Reaper deals 1 damage to you and you draw a card. | Sidharth Chaturvedi

Etrata, the Silencer | Legendary Creature | Vampire Assassin | Etrata, the Silencer can't be blocked. Whenever Etrata deals combat damage to a player, exile target creature that player controls and put a hit counter on that card. That player loses the game if they own three or more exiled cards with hit counters on them. Etrata's owner shuffles Etrata into their library. | Bastien L. Deharme

Thief of Sanity | Creature | Specter | Flying Whenever Thief of Sanity deals combat damage to a player, look at the top three cards of that player's library, exile one of them face down, then put the rest into their graveyard. You may look at and cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell. | Igor Kieryluk

Charnel Troll | Creature | Troll | Trample At the beginning of your upkeep, exile a creature card from your graveyard. If you do, put a +1/+1 counter on Charnel Troll. Otherwise, sacrifice it. {B}{G}, Discard a creature card: Put a +1/+1 counter on Charnel Troll. | Daniel Ljunggren

Izoni, Thousand-Eyed | Legendary Creature | Elf Shaman | Undergrowth — When Izoni, Thousand-Eyed enters the battlefield, create a 1/1 black and green Insect creature token for each creature card in your graveyard. {B}{G}, Sacrifice another creature: You gain 1 life and draw a card. | Eric Deschamps

Chamber Sentry | Artifact Creature | Construct | Chamber Sentry enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it. {X}, {T}, Remove X +1/+1 counters from Chamber Sentry: It deals X damage to any target. {W}{U}{B}{R}{G}: Return Chamber Sentry from your graveyard to your hand. | Adam Paquette