Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Negate

Azorius Guildgate

Azorius Guildgate enters tapped.
{T}: Add {W} or {U}.

Not Dead After All

Until end of turn, target creature you control gains "When this creature dies, return it to the battlefield tapped under its owner's control, then create a Wicked Role token attached to it." (Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Orzhov Guildgate

Orzhov Guildgate enters tapped.
{T}: Add {W} or {B}.

Echo Inspector

Flying
When Echo Inspector enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Steady Progress

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Murder

Raffine's Informant

When Raffine's Informant enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Swamp

Plains

Contentious Plan

Island

Revel Ruiner

Menace (This creature can't be blocked except by two or more creatures.)
When Revel Ruiner enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Boon of Safety

Put a shield counter on target creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
Scry 1.

Psionic Snoop

Flash
When Psionic Snoop enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)