Guilds of Ravnica

Drowned Secrets | Enchantment | | Whenever you cast a blue spell, target player mills two cards. | Alexander Forssberg

Mission Briefing | Instant | | Surveil 2, then choose an instant or sorcery card in your graveyard. You may cast it this turn. If that spell would be put into your graveyard, exile it instead. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) | Matt Stewart

Narcomoeba | Creature | Illusion | Flying When Narcomoeba is put into your graveyard from your library, you may put it onto the battlefield. | Howard Lyon

Omnispell Adept | Creature | Human Wizard | {2}{U}, {T}: You may cast an instant or sorcery spell from your hand without paying its mana cost. | Jason Rainville

Quasiduplicate | Sorcery | | Create a token that's a copy of target creature you control. Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.) | Dmitry Burmak

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

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

Steam Vents | Land | Island Mountain | ({T}: Add {U} or {R}.) As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped. | Jonas De Ro

Watery Grave | Land | Island Swamp | ({T}: Add {U} or {B}.) As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped. | Cliff Childs