Horn of Greed

Whenever a player plays a land, that player draws a card.

Ghirapur Orrery

Each player may play an additional land on each of their turns.
At the beginning of each player's upkeep, if that player has no cards in hand, that player draws three cards.

Spellshock

Whenever a player casts a spell, Spellshock deals 2 damage to that player.

Primal Vigor

If one or more tokens would be created, twice that many of those tokens are created instead.
If one or more +1/+1 counters would be put on a creature, twice that many +1/+1 counters are put on that creature instead.

Humility

All creatures lose all abilities and have base power and toughness 1/1.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Orb of Dreams

Dictate of the Twin Gods

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

Eye of the Storm

Whenever a player casts an instant or sorcery card, exile it. Then that player copies each instant or sorcery card exiled with Eye of the Storm. For each copy, the player may cast the copy without paying its mana cost.

Rites of Flourishing

At the beginning of each player's draw step, that player draws an additional card.
Each player may play an additional land on each of their turns.

Thorn of Amethyst

Noncreature spells cost {1} more to cast.

Concordant Crossroads

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Helm of Awakening

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Vernal Equinox

Any player may cast creature and enchantment spells as though they had flash.

Anvil of Bogardan

Players have no maximum hand size.
At the beginning of each player's draw step, that player draws an additional card, then discards a card.

Eladamri's Vineyard

At the beginning of each player's first main phase, that player adds {G}{G}.

Awakening

At the beginning of each upkeep, untap all creatures and lands.

Gate to the Aether

At the beginning of each player's upkeep, that player reveals the top card of their library. If it's an artifact, creature, enchantment, or land card, the player may put it onto the battlefield.

Blood Moon

Fecundity

Whenever a creature dies, that creature's controller may draw a card.

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.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

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.

Endless Whispers

Each creature has "When this creature dies, choose target opponent. That player puts this card from its owner's graveyard onto the battlefield under their control at the beginning of the next end step."

Solemnity

Players can't get counters.
Counters can't be put on artifacts, creatures, enchantments, or lands.

Mycosynth Lattice

All permanents are artifacts in addition to their other types.
All cards that aren't on the battlefield, spells, and permanents are colorless.
Players may spend mana as though it were mana of any color.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Wild Evocation

At the beginning of each player's upkeep, that player reveals a card at random from their hand. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.

Aether Barrier

Whenever a player casts a creature spell, that player sacrifices a permanent of their choice unless they pay {1}.

Upwelling

Players don't lose unspent mana as steps and phases end.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Enchanted Evening

All permanents are enchantments in addition to their other types.

Furnace of Rath

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