Gain control of target spell. You may choose new targets for it. (If that spell becomes a permanent, it enters the battlefield under your control.)

Defender

When Akroan Horse enters the battlefield, an opponent gains control of it.

At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Enchant creature card in a graveyard

When Animate Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.

Enchanted creature gets -1/-0.

Equipped creature gets +2/+2, has haste, can't attack you or planeswalkers you control, and can't be sacrificed.

At the beginning of each opponent's upkeep, you may have that player gain control of equipped creature until end of turn. If you do, untap it.

Equip {3}

Flying

When Aura Thief dies, you gain control of all enchantments. (You don't get to move Auras.)

{T}: Gain control of target creature with power less than or equal to the number of creatures you control.

For each opponent, gain control of target permanent that player controls.

Other Vampire creatures you control get +1/+1.

Tap five untapped Vampires you control: Gain control of target creature. It becomes a Vampire in addition to its other types.

Enchant creature

Whenever enchanted creature deals damage to a creature, gain control of the other creature for as long as Charisma remains on the battlefield.

Choose target artifact or creature. You get {E}{E}{E}{E} (four energy counters), then you may pay an amount of {E} equal to that permanent's mana value. If you do, gain control of it.

Regenerate target creature. You gain control of that creature if it regenerates this way.

Gain control of target creature with mana value X or less.

Target player gains control of target permanent you control.

Flying, deathtouch

When Dragonlord Silumgar enters the battlefield, gain control of target creature or planeswalker for as long as you control Dragonlord Silumgar.

{U}{U}, {T}: Gain control of target legendary permanent. (This effect lasts indefinitely.)

This spell costs {1} less to cast for each card type among cards in your graveyard.

When you cast this spell, you gain control of target opponent during that player's next turn. After that turn, that player takes an extra turn.

Flying, trample, protection from instants

Buyback {2}{W}{W} (You may pay an additional {2}{W}{W} as you cast this spell. If you do, put this card into your hand as it resolves.)

Gain control of target creature of an opponent's choice they control.

Council's dilemma -- Starting with you, each player votes for time or money. For each time vote, take an extra turn after this one. For each money vote, choose a permanent owned by the voter and gain control of it. Exile Expropriate.

Put target creature card from a graveyard onto the battlefield under your control. It gains indestructible. If it's your turn, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.

{3}, Sacrifice Glaring Spotlight: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Gain control of target monocolored creature.

Forecast -- {1}{U}, Reveal Govern the Guildless from your hand: Target creature becomes the color or colors of your choice until end of turn. (Activate only during your upkeep and only once each turn.)

Gain control of target Equipment, then create a 0/0 black Phyrexian Germ creature token and attach that Equipment to it.

You may choose not to untap Helm of Possession during your untap step.

{2}, {T}, Sacrifice a creature: Gain control of target creature for as long as you control Helm of Possession and Helm of Possession remains tapped.

Flying

Cumulative upkeep--Gain control of a land you don't control. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Herald of Leshrac gets +1/+1 for each land you control but don't own.

When Herald of Leshrac leaves the battlefield, each player gains control of each land they own that you control.

Enchant creature

You control enchanted creature.

Whenever a creature enters the battlefield under an opponent's control, attach Illusory Gains to that creature.

Flying

When Keiga, the Tide Star dies, gain control of target creature.

{1}{U}, {T}: Untap target artifact an opponent controls and gain control of it until end of turn. It gains haste until end of turn. When you lose control of the artifact, tap it.

When Master Thief enters the battlefield, gain control of target artifact for as long as you control Master Thief.

When Master Thief enters the battlefield, gain control of target artifact for as long as you control Master Thief.

When Master Thief enters the battlefield, gain control of target artifact for as long as you control Master Thief.

{4}, {T}, Sacrifice Mindslaver: You control target player during that player's next turn. (You see all cards that player could see and make all decisions for the player.)

At the beginning of your upkeep, choose target opponent. This turn, that player can't cast spells or activate abilities and plays with their hand revealed. You may play lands and cast spells from that player's hand this turn.