Guilds of Ravnica

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

Unmoored Ego | Sorcery | | Choose a card name. Search target opponent's graveyard, hand, and library for up to four cards with that name and exile them. That player shuffles, then draws a card for each card exiled from their hand this way. | Volkan Baǵa

Connive | Sorcery | | Gain control of target creature with power 2 or less. | Dan Scott

Firemind's Research | Enchantment | | Whenever you cast an instant or sorcery spell, put a charge counter on Firemind's Research. {1}{U}, Remove two charge counters from Firemind's Research: Draw a card. {1}{R}, Remove five charge counters from Firemind's Research: It deals 5 damage to any target. | Grzegorz Rutkowski

Ionize | Instant | | Counter target spell. Ionize deals 2 damage to that spell's controller. | Chase Stone

Niv-Mizzet, Parun | Legendary Creature | Dragon Wizard | This spell can't be countered. Flying Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target. Whenever a player casts an instant or sorcery spell, you draw a card. | Svetlin Velinov

Expansion | Instant | | Copy target instant or sorcery spell with mana value 4 or less. You may choose new targets for the copy. | Deruchenko Alexander