Have

Word of Seizing

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Untap target permanent and gain control of it until end of turn. It gains haste until end of turn.

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

Getting

Yuffie, Materia Hunter

Ninjutsu {1}{R} ({1}{R}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Yuffie enters, gain control of target noncreature artifact for as long as you control Yuffie. Then you may attach an Equipment you control to Yuffie.

Zidane, Tantalus Thief

When Zidane enters, gain control of target creature an opponent controls until end of turn. Untap it. It gains lifelink and haste until end of turn.
Whenever an opponent gains control of a permanent from you, you create a Treasure token.

Another Round

Exile any number of creatures you control, then return them to the battlefield under their owner's control. Then repeat this process X more times.

Bazaar Trader

{T}: Target player gains control of target artifact, creature, or land you control.

Stiltzkin, Moogle Merchant

Lifelink
{2}, {T}: Target opponent gains control of another target permanent you control. If they do, you draw a card.

Duke Ulder Ravengard

At the beginning of combat on your turn, another target creature you control gains haste and myriad until end of turn. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Galepowder Mage

Flying
Whenever this creature attacks, exile another target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Mass Mutiny

For each opponent, gain control of up to one target creature that player controls until end of turn. Untap those creatures. They gain haste until end of turn.

Suplex

Choose one —
• Suplex deals 3 damage to target creature. If that creature would die this turn, exile it instead.
• Exile target artifact.

Claim the Firstborn

Gain control of target creature with mana value 3 or less until end of turn. Untap that creature. It gains haste until end of turn.

Infernal Captor

Exploit (When this creature enters, you may sacrifice a creature.)
When this creature exploits a creature, gain control of target artifact or creature until end of turn. Untap that permanent. It gains haste until end of turn.

Foundry Helix

As an additional cost to cast this spell, sacrifice a permanent.
Foundry Helix deals 4 damage to any target. If the sacrificed permanent was an artifact, you gain 4 life.

Captivating Crew

{3}{R}: Gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn. Activate only as a sorcery.

Bloodshot Cyclops

{T}, Sacrifice a creature: This creature deals damage equal to the sacrificed creature's power to any target.

Vaan, Street Thief

Whenever one or more Scouts, Pirates, and/or Rogues you control deal combat damage to a player, exile the top card of that player's library. You may cast it. If you don't, create a Treasure token.
Whenever you cast a spell you don't own, put a +1/+1 counter on each Scout, Pirate, and Rogue you control.

Zealous Conscripts

Haste
When this creature enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.

Conquering Manticore

Flying
When this creature enters, gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.

Rescue the Foal

Exile target creature you control, then return that card to the battlefield under its owner's control. (Then exile this card. You may cast the creature later from exile.)

Pegasus Guardian

Flying
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, create a 1/1 white Pegasus creature token with flying.

Pegasus Guardian // Rescue the Foal

Flickerwisp

Flying
When this creature enters, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Jeering Instigator

Morph {2}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When this creature is turned face up, if it's your turn, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

Rowan, Fearless Sparkmage

+1: Up to one target creature gets +3/+0 and gains first strike until end of turn.
−2: Rowan deals 1 damage to each of up to two target creatures. Those creatures can't block this turn.
−9: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Molten Primordial

Haste
When this creature enters, for each opponent, gain control of up to one target creature that player controls until end of turn. Untap those creatures. They gain haste until end of turn.

Sun Titan

Vigilance
Whenever this creature enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Humble Defector

{T}: Draw two cards. Target opponent gains control of this creature. Activate only during your turn.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Flicker

Exile target nontoken permanent, then return it to the battlefield under its owner's control.

Nahiri's Resolve

Creatures you control get +1/+0 and have haste.
At the beginning of your end step, exile any number of nontoken artifacts and/or creatures you control. Return those cards to the battlefield under their owner's control at the beginning of your next upkeep.

Seize the Spotlight

Each opponent chooses fame or fortune. For each player who chose fame, gain control of a creature that player controls until end of turn. Untap those creatures and they gain haste until end of turn. For each player who chose fortune, you draw a card and create a Treasure token.

Eriette's Tempting Apple

When Eriette's Tempting Apple enters, gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
{2}, {T}, Sacrifice Eriette's Tempting Apple: You gain 3 life.
{2}, {T}, Sacrifice Eriette's Tempting Apple: Target opponent loses 3 life.

Mob Rule

Choose one —
• Gain control of all creatures with power 4 or greater until end of turn. Untap those creatures. They gain haste until end of turn.
• Gain control of all creatures with power 3 or less until end of turn. Untap those creatures. They gain haste until end of turn.

Metallic Mastery

Gain control of target artifact until end of turn. Untap that artifact. It gains haste until end of turn.

Involuntary Employment

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Alexios, Deimos of Kosmos

Trample
Alexios attacks each combat if able, can't be sacrificed, and can't attack its owner.
At the beginning of each player's upkeep, that player gains control of Alexios, untaps it, and puts a +1/+1 counter on it. It gains haste until end of turn.

Unexpected Request

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. You may attach an Equipment you control to that creature. If you do, unattach it at the beginning of the next end step.

The Jolly Balloon Man

Haste
{1}, {T}: Create a token that's a copy of another target creature you control, except it's a 1/1 red Balloon creature in addition to its other colors and types and it has flying and haste. Sacrifice it at the beginning of the next end step. Activate only as a sorcery.

Restoration Angel

Flash
Flying
When this creature enters, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Parting Gust

Gift a tapped Fish (You may promise an opponent a gift as you cast this spell. If you do, they create a tapped 1/1 blue Fish creature token before its other effects.)
Exile target nontoken creature. If the gift wasn't promised, return that card to the battlefield under its owner's control with a +1/+1 counter on it at the beginning of the next end step.

Avarice Amulet

Equipped creature gets +2/+0 and has vigilance and "At the beginning of your upkeep, draw a card."
Whenever equipped creature dies, target opponent gains control of this Equipment.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

You're Not Alone

Target creature gets +2/+2 until end of turn. If you control three or more creatures, it gets +4/+4 until end of turn instead.