Clawing Torment

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets -1/-1 and can't block.
Enchanted permanent has "At the beginning of your upkeep, you lose 1 life."

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.")

Network Terminal

{T}: Add one mana of any color.
{1}, {T}, Tap another untapped artifact you control: Draw a card, then discard a card.

Golgari Signet

Inkrise Infiltrator

Flying
{3}{B}: Inkrise Infiltrator gets +2/+2 until end of turn.

Ninja's Kunai

Equipped creature has "{1}, {T}, Sacrifice Ninja's Kunai: Ninja's Kunai deals 3 damage to any target."
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Thornwood Falls

Thornwood Falls enters tapped.
When Thornwood Falls enters, you gain 1 life.
{T}: Add {G} or {U}.

Deal Gone Bad

Target creature gets -3/-3 until end of turn. Target player mills three cards. (They put the top three cards of their library into their graveyard.)

Fang of Shigeki

Waterfront District

Waterfront District enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice Waterfront District: Draw a card.

Forest

Mirrorshell Crab

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Channel — {2}{U}, Discard Mirrorshell Crab: Counter target spell or ability unless its controller pays {3}.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Dimir Signet

Broken Wings

Destroy target artifact, enchantment, or creature with flying.

Swamp

Smoke Shroud

Enchant creature
Enchanted creature gets +1/+1 and has flying.
When a Ninja you control enters, you may return Smoke Shroud from your graveyard to the battlefield attached to that creature.

Dokuchi Shadow-Walker

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

Gilded Pinions

When Gilded Pinions enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equipped creature has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Quick-Draw Dagger

Flash
When Quick-Draw Dagger enters, attach it to target creature you control. That creature gains first strike until end of turn.
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Island

Scoured Barrens

Scoured Barrens enters tapped.
When Scoured Barrens enters, you gain 1 life.
{T}: Add {W} or {B}.

Moon-Circuit Hacker

Ninjutsu {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Moon-Circuit Hacker deals combat damage to a player, you may draw a card. If you do, discard a card unless Moon-Circuit Hacker entered this turn.

Coiling Stalker

Ninjutsu {1}{G} ({1}{G}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Coiling Stalker deals combat damage to a player, put a +1/+1 counter on target creature you control that doesn't have a +1/+1 counter on it.

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink