Nether Void

Whenever a player casts a spell, counter it unless that player pays {3}.

Turn to Frog

Until end of turn, target creature loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Humble

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Dress Down

Flash
When Dress Down enters, draw a card.
Creatures lose all abilities.
At the beginning of the end step, sacrifice Dress Down.

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Zur, Eternal Schemer

Flying
Enchantment creatures you control have deathtouch, lifelink, and hexproof.
{1}{W}: Target non-Aura enchantment you control becomes a creature in addition to its other types and has base power and base toughness each equal to its mana value.

Gift of Tusks

Until end of turn, target creature loses all abilities and becomes a green Elephant with base power and toughness 3/3.

Opalescence

Each other non-Aura enchantment is a creature in addition to its other types and has base power and base toughness each equal to its mana value.