Dispersal Shield

Counter target spell if its mana value is less than or equal to the highest mana value among permanents you control.

Thundercloud Elemental

Flying
{3}{U}: Tap all creatures with toughness 2 or less.
{3}{U}: All other creatures lose flying until end of turn.

Torrent of Fire

Torrent of Fire deals damage to any target equal to the highest mana value among permanents you control.

Bloodstoke Howler

Morph {6}{R} (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 Bloodstoke Howler is turned face up, Beast creatures you control get +3/+0 until end of turn.

Mountain

Scornful Egotist

Morph {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.)

Pyrostatic Pillar

Whenever a player casts a spell with mana value 3 or less, Pyrostatic Pillar deals 2 damage to that player.

Goblin Machinist

{2}{R}: Reveal cards from the top of your library until you reveal a nonland card. Goblin Machinist gets +X/+0 until end of turn, where X is that card's mana value. Put the revealed cards on the bottom of your library in any order.

Slice and Dice

Slice and Dice deals 4 damage to each creature.
Cycling {2}{R} ({2}{R}, Discard this card: Draw a card.)
When you cycle Slice and Dice, you may have it deal 1 damage to each creature.

Aven Fateshaper

Flying
When Aven Fateshaper enters, look at the top four cards of your library, then put them back in any order.
{4}{U}: Look at the top four cards of your library, then put them back in any order.

Carbonize

Carbonize deals 3 damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

Island

Macetail Hystrodon

First strike, haste
Cycling {3} ({3}, Discard this card: Draw a card.)

Rush of Knowledge

Draw cards equal to the highest mana value among permanents you control.

Dragon Breath

Enchant creature
Enchanted creature has haste.
{R}: Enchanted creature gets +1/+0 until end of turn.
When a creature with mana value 6 or greater enters, you may return Dragon Breath from your graveyard to the battlefield attached to that creature.

Erratic Explosion

Choose any target. Reveal cards from the top of your library until you reveal a nonland card. Erratic Explosion deals damage equal to that card's mana value to that permanent or player. Put the revealed cards on the bottom of your library in any order.

Parallel Thoughts

When Parallel Thoughts enters, search your library for seven cards, exile them in a face-down pile, and shuffle that pile. Then shuffle your library.
If you would draw a card, you may instead put the top card of the pile you exiled into your hand.

Frenetic Raptor

Shoreline Ranger

Flying
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Mistform Warchief

Creature spells you cast that share a creature type with Mistform Warchief cost {1} less to cast.
{T}: Mistform Warchief becomes the creature type of your choice until end of turn.

Chartooth Cougar

{R}: Chartooth Cougar gets +1/+0 until end of turn.
Mountaincycling {2} ({2}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Skittish Valesk

At the beginning of your upkeep, flip a coin. If you lose the flip, turn Skittish Valesk face down.
Morph {5}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Mischievous Quanar

{3}{U}{U}: Turn Mischievous Quanar face down.
Morph {1}{U}{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 Mischievous Quanar is turned face up, copy target instant or sorcery spell. You may choose new targets for that copy.