Frost Trickster

Flying
When Frost Trickster enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Island

Traumatic Prank

Gain control of target creature until end of turn. Untap that creature. It perpetually gains haste, "This creature can't block," and "At the beginning of your upkeep, this creature deals 1 damage to you."

Zalto, Fire Giant Duke

Trample
Whenever Zalto, Fire Giant Duke is dealt damage, venture into the dungeon. (Enter the first room or advance to the next room.)

Swiftwater Cliffs

Swiftwater Cliffs enters tapped.
When Swiftwater Cliffs enters, you gain 1 life.
{T}: Add {U} or {R}.

Blue Dragon

Flying
Lightning Breath — When Blue Dragon enters, until your next turn, target creature an opponent controls gets -3/-0, up to one other target creature gets -2/-0, and up to one other target creature gets -1/-0.

Mountain

Thundering Rebuke

Thundering Rebuke deals 4 damage to target creature or planeswalker.

Calamity Bearer

If a Giant source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Fifty Feet of Rope

Climb Over — {T}: Target Wall can't block this turn.
Tie Up — {3}, {T}: Target creature doesn't untap during its controller's next untap step.
Rappel Down — {4}, {T}: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Volcanic Dragon

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Involuntary Employment

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Cyclone Summoner

When Cyclone Summoner enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Warden of Evos Isle

Flying
Creature spells with flying you cast cost {1} less to cast.

Siege Dragon

Flying
When Siege Dragon enters, destroy all Walls your opponents control.
Whenever Siege Dragon attacks, if defending player controls no Walls, it deals 2 damage to each creature without flying that player controls.

Majestic Metamorphosis

Until end of turn, target artifact or creature becomes a 4/4 Angel artifact creature and gains flying.
Draw a card.

Run Amok

Target attacking creature gets +3/+3 and gains trample until end of turn.

Red Dragon

Flying
Fire Breath — When Red Dragon enters, it deals 4 damage to each opponent.

Inferno of the Star Mounts

This spell can't be countered.
Flying, haste
{R}: Inferno of the Star Mounts gets +1/+0 until end of turn. When its power becomes 20 this way, it deals 20 damage to any target.

Charmed Sleep

Enchant creature
When Charmed Sleep enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Reinforced Ronin

Haste
At the beginning of your end step, return Reinforced Ronin to its owner's hand.
Channel — {1}{R}, Discard Reinforced Ronin: Draw a card.

Cloudkin Seer

Flying
When Cloudkin Seer enters, draw a card.

Mind Flayer

Dominate Monster — When Mind Flayer enters, gain control of target creature for as long as you control Mind Flayer.

Mordenkainen's Polymorph

Until end of turn, target creature becomes a Dragon with base power and toughness 4/4 and gains flying. (It loses all other creature types.)