Warp World

Each player shuffles all permanents they own into their library, then reveals that many cards from the top of their library. Each player puts all artifact, creature, and land cards revealed this way onto the battlefield, then does the same for enchantment cards, then puts all cards revealed this way that weren't put onto the battlefield on the bottom of their library.

Magmatic Core

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
At the beginning of your end step, Magmatic Core deals X damage divided as you choose among any number of target creatures, where X is the number of age counters on it.

Swamp

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Mountain

Tresserhorn Skyknight

Flying
Prevent all damage that would be dealt to Tresserhorn Skyknight by creatures with first strike.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Wall of Fire

Defender (This creature can't attack.)
{R}: Wall of Fire gets +1/+0 until end of turn.

Grim Harvest

Return target creature card from your graveyard to your hand.
Recover {2}{B} (When a creature is put into your graveyard from the battlefield, you may pay {2}{B}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Chill to the Bone

Cemetery Gate

Defender (This creature can't attack.)
Protection from black

Gutless Ghoul

{1}, Sacrifice a creature: You gain 2 life.

Gristle Grinner

Whenever a creature dies, Gristle Grinner gets +2/+2 until end of turn.

Cloak and Dagger

Equipped creature gets +2/+0 and has shroud. (It can't be the target of spells or abilities.)
Whenever a Rogue creature enters, you may attach Cloak and Dagger to it.
Equip {3}

Disintegrate

Disintegrate deals X 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.

Martyr of Ashes

{2}, Reveal X red cards from your hand, Sacrifice Martyr of Ashes: Martyr of Ashes deals X damage to each creature without flying.

Deepfire Elemental

{X}{X}{1}: Destroy target artifact or creature with mana value X.

Herald of Leshrac

Flying
Cumulative upkeep—Gain control of a land you don't control. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Herald of Leshrac gets +1/+1 for each land you control but don't own.
When Herald of Leshrac leaves the battlefield, each player gains control of each land they own that you control.

Disciple of Tevesh Szat

{T}: Target creature gets -1/-1 until end of turn.
{4}{B}{B}, {T}, Sacrifice Disciple of Tevesh Szat: Target creature gets -6/-6 until end of turn.

Void Maw

Trample
If another creature would die, exile it instead.
Put a card exiled with Void Maw into its owner's graveyard: Void Maw gets +2/+2 until end of turn.

Wall of Shadows

Defender (This creature can't attack.)
Prevent all damage that would be dealt to Wall of Shadows by creatures it's blocking.
Wall of Shadows can't be the target of spells that can target only Walls or of abilities that can target only Walls.

Inferno Elemental

Whenever Inferno Elemental blocks or becomes blocked by a creature, Inferno Elemental deals 3 damage to that creature.