Custody Battle

Enchant creature
Enchanted creature has "At the beginning of your upkeep, target opponent gains control of this creature unless you sacrifice a land."

Charmed Griffin

Flying
When Charmed Griffin enters, each other player may put an artifact or enchantment card onto the battlefield from their hand.

Brooding Saurian

At the beginning of each end step, each player gains control of all nontoken permanents they own.

Hunted Wumpus

When Hunted Wumpus enters, each other player may put a creature card from their hand onto the battlefield.

Tempting Wurm

When Tempting Wurm enters, each opponent may put any number of artifact, creature, enchantment, and/or land cards from their hand onto the battlefield.

Emberwilde Djinn

Flying
At the beginning of each player's upkeep, that player may pay {R}{R} or 2 life. If the player does, they gain control of Emberwilde Djinn.

Bazaar Trader

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

Harmless Offering

Target opponent gains control of target permanent you control.

Rohgahh of Kher Keep

At the beginning of your upkeep, you may pay {R}{R}{R}. If you don't, tap Rohgahh of Kher Keep and all creatures named Kobolds of Kher Keep, then an opponent gains control of them.
Creatures you control named Kobolds of Kher Keep get +2/+2.

Crag Saurian

Whenever a source deals damage to Crag Saurian, that source's controller gains control of Crag Saurian.

Loxodon Peacekeeper

At the beginning of your upkeep, the player with the lowest life total gains control of Loxodon Peacekeeper. If two or more players are tied for lowest life total, you choose one of them, and that player gains control of Loxodon Peacekeeper.

Clear the Land

Each player reveals the top five cards of their library, puts all land cards revealed this way onto the battlefield tapped, and exiles the rest.

Hired Giant

When Hired Giant enters, each other player may search their library for a land card and put that card onto the battlefield. Then each player who searched their library this way shuffles.

Ghazbán Ogre

At the beginning of your upkeep, if a player has more life than each other player, the player with the most life gains control of Ghazbán Ogre.

Indentured Djinn

Flying
When Indentured Djinn enters, each other player may draw up to three cards.

Treacherous Pit-Dweller

When Treacherous Pit-Dweller enters from a graveyard, target opponent gains control of it.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Drooling Ogre

Whenever a player casts an artifact spell, that player gains control of Drooling Ogre. (This effect lasts indefinitely.)

Rogue Skycaptain

Flying
At the beginning of your upkeep, put a wage counter on Rogue Skycaptain. You may pay {2} for each wage counter on it. If you don't, remove all wage counters from Rogue Skycaptain and an opponent gains control of it.

Varchild, Betrayer of Kjeldor

Whenever Varchild, Betrayer of Kjeldor deals combat damage to a player, that player creates that many 1/1 red Survivor creature tokens.
Survivors your opponents control can't block, and they can't attack you or planeswalkers you control.
When Varchild leaves the battlefield, gain control of all Survivors.

Rainbow Vale

{T}: Add one mana of any color. An opponent gains control of Rainbow Vale at the beginning of the next end step.

Varchild's War-Riders

Cumulative upkeep—Have an opponent create a 1/1 red Survivor creature token. (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.)
Trample; rampage 1 (Whenever this creature becomes blocked, it gets +1/+1 until end of turn for each creature blocking it beyond the first.)

Sleeper Agent

When Sleeper Agent enters, target opponent gains control of it.
At the beginning of your upkeep, Sleeper Agent deals 2 damage to you.

Boldwyr Heavyweights

Trample
When Boldwyr Heavyweights enters, each opponent may search their library for a creature card and put it onto the battlefield. Then each player who searched their library this way shuffles.

Wild Mammoth

At the beginning of your upkeep, if a player controls more creatures than each other player, the player who controls the most creatures gains control of Wild Mammoth.

Enslaved Horror

When Enslaved Horror enters, each other player may return a creature card from their graveyard to the battlefield.

Fickle Efreet

Whenever Fickle Efreet attacks or blocks, flip a coin at end of combat. If you lose the flip, an opponent gains control of Fickle Efreet.