Merieke Ri Berit

Merieke Ri Berit doesn't untap during your untap step.
{T}: Gain control of target creature for as long as you control Merieke Ri Berit. When Merieke Ri Berit leaves the battlefield or becomes untapped, destroy that creature. It can't be regenerated.

Debt of Loyalty

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

Shield Broker

When Shield Broker enters, put a shield counter on target noncommander creature you don't control. You gain control of that creature for as long as it has a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Jabari's Influence

Cast this spell only after combat.
Gain control of target nonartifact, nonblack creature that attacked you this turn and put a -1/-0 counter on it.

Preacher

You may choose not to untap Preacher during your untap step.
{T}: For as long as Preacher remains tapped, gain control of target creature of an opponent's choice they control.

Chamber of Manipulation

Enchant land
Enchanted land has "{T}, Discard a card: Gain control of target creature until end of turn."

Cytoplast Manipulator

Graft 2 (This creature enters with two +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{U}, {T}: Gain control of target creature with a +1/+1 counter on it for as long as Cytoplast Manipulator remains on the battlefield.

Overtaker

{3}{U}, {T}, Discard a card: Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Sower of Temptation

Flying
When Sower of Temptation enters, gain control of target creature for as long as Sower of Temptation remains on the battlefield.

Vedalken Shackles

You may choose not to untap Vedalken Shackles during your untap step.
{2}, {T}: Gain control of target creature with power less than or equal to the number of Islands you control for as long as Vedalken Shackles remains tapped.

Roil Elemental

Flying
Landfall — Whenever a land you control enters, you may gain control of target creature for as long as you control Roil Elemental.

The Ever-Changing 'Dane

{1}, Sacrifice another creature: The Ever-Changing 'Dane becomes a copy of the sacrificed creature, except it has this ability.

Evangelize

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.

Callous Oppressor

You may choose not to untap Callous Oppressor during your untap step.
As Callous Oppressor enters, an opponent chooses a creature type.
{T}: Gain control of target creature that isn't of the chosen type for as long as Callous Oppressor remains tapped.

Ray of Command

Untap target creature an opponent controls and gain control of it until end of turn. That creature gains haste until end of turn. When you lose control of the creature, tap it.