Chromeshell Crab

Morph {4}{U} (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 Chromeshell Crab is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Shifting Loyalties

Exchange control of two target permanents that share a card type. (Artifact, creature, enchantment, land, and planeswalker are card types.)

Daring Thief

Inspired — Whenever Daring Thief becomes untapped, you may exchange control of target nonland permanent you control and target permanent an opponent controls that shares a card type with it.

Guilty Conscience

Enchant creature
Whenever enchanted creature deals damage, Guilty Conscience deals that much damage to that creature.

Martyrdom

Until end of turn, target creature you control gains "{0}: The next 1 damage that would be dealt to target creature, planeswalker, or player this turn is dealt to this creature instead." Only you may activate this ability.

Saving Grace

Flash
Enchant creature you control
When Saving Grace enters, all damage that would be dealt this turn to you and permanents you control is dealt to enchanted creature instead.
Enchanted creature gets +0/+3.

Truefire Captain

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Truefire Captain is dealt damage, it deals that much damage to target player.

Pariah's Shield

All damage that would be dealt to you is dealt to equipped creature instead.
Equip {3}

Switcheroo

Exchange control of two target creatures.

Modify Memory

Exchange control of two target creatures controlled by different players. If you control neither creature, draw three cards.

Cultural Exchange

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

Spiteful Shadows

Enchant creature
Whenever enchanted creature is dealt damage, it deals that much damage to its controller.

Gideon's Sacrifice

Choose a creature or planeswalker you control. All damage that would be dealt this turn to you and permanents you control is dealt to the chosen permanent instead (if it's still on the battlefield).

Puca's Mischief

At the beginning of your upkeep, you may exchange control of target nonland permanent you control and target nonland permanent an opponent controls with equal or lesser mana value.

Spitemare

Whenever Spitemare is dealt damage, it deals that much damage to any target.

The Trickster-God's Heist

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — You may exchange control of two target creatures.
II — You may exchange control of two target nonbasic, noncreature permanents that share a card type.
III — Target player loses 3 life and you gain 3 life.

Boros Reckoner

Whenever Boros Reckoner is dealt damage, it deals that much damage to any target.
{R/W}: Boros Reckoner gains first strike until end of turn.

Perplexing Chimera

Whenever an opponent casts a spell, you may exchange control of Perplexing Chimera and that spell. If you do, you may choose new targets for the spell. (If the spell becomes a permanent, you control that permanent.)

Pariah

Enchant creature
All damage that would be dealt to you is dealt to enchanted creature instead.

Legerdemain

Exchange control of target artifact or creature and another target permanent that shares one of those types with it. (This effect lasts indefinitely.)