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.)

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Shimmering Glasskite

Flying
Whenever Shimmering Glasskite becomes the target of a spell or ability for the first time each turn, counter that spell or ability.

Silver Myr

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Aura Thief

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

Jetting Glasskite

Flying
Whenever Jetting Glasskite becomes the target of a spell or ability for the first time each turn, counter that spell or ability.

Simic Manipulator

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}, Remove one or more +1/+1 counters from Simic Manipulator: Gain control of target creature with power less than or equal to the number of +1/+1 counters removed this way.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Clone Legion

For each creature target player controls, create a token that's a copy of that creature.

Reins of Power

Untap all creatures you control and all creatures target opponent controls. You and that opponent each gain control of all creatures the other controls until end of turn. Those creatures gain haste until end of turn.

Steal Enchantment

Enchant enchantment
You control enchanted enchantment.

Unsummon

Return target creature to its owner's hand.

Control Magic

Enchant creature
You control enchanted creature.

Counterspell

Island

Soul Foundry

Imprint — When Soul Foundry enters, you may exile a creature card from your hand.
{X}, {T}: Create a token that's a copy of the exiled card. X is the mana value of that card.

Keiga, the Tide Star

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

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Hive Mind

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

Chamber of Manipulation

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