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

Legion Warboss | Creature | Goblin Soldier | Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) At the beginning of combat on your turn, create a 1/1 red Goblin creature token. That token gains haste until end of turn and attacks this combat if able. | Alex Konstad

Tajic, Legion's Edge | Legendary Creature | Human Soldier | Haste Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) Prevent all noncombat damage that would be dealt to other creatures you control. {R}{W}: Tajic, Legion's Edge gains first strike until end of turn. | Anthony Palumbo

Knight of Autumn | Creature | Dryad Knight | When Knight of Autumn enters the battlefield, choose one — • Put two +1/+1 counters on Knight of Autumn. • Destroy target artifact or enchantment. • You gain 4 life. | Ryan Pancoast

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