Aether Storm

Creature spells can't be cast.
Pay 4 life: Destroy Aether Storm. It can't be regenerated. Any player may activate this ability.

Aluren

Any player may cast creature spells with mana value 3 or less without paying their mana costs and as though they had flash.

Argothian Wurm

Trample
When Argothian Wurm enters, any player may sacrifice a land. If a player does, put Argothian Wurm on top of its owner's library.

Book Burning

Any player may have Book Burning deal 6 damage to them. If no one does, target player mills six cards.

Breaking Point

Any player may have Breaking Point deal 6 damage to them. If no one does, destroy all creatures. Creatures destroyed this way can't be regenerated.

Browbeat

Any player may have Browbeat deal 5 damage to them. If no one does, target player draws three cards.

Dash Hopes

When you cast this spell, any player may pay 5 life. If a player does, counter Dash Hopes.
Counter target spell.

Deadly Designs

{2}: Put a plot counter on Deadly Designs. Any player may activate this ability.
When there are five or more plot counters on Deadly Designs, sacrifice it. If you do, destroy up to two target creatures.

Excavation

{1}, Sacrifice a land: Draw a card. Any player may activate this ability.

Endbringer's Revel

{4}: Return target creature card from a graveyard to its owner's hand. Any player may activate this ability but only as a sorcery.

Feral Hydra

Feral Hydra enters with X +1/+1 counters on it.
{3}: Put a +1/+1 counter on Feral Hydra. Any player may activate this ability.

Land's Edge

Discard a card: If the discarded card was a land card, Land's Edge deals 2 damage to target player or planeswalker. Any player may activate this ability.

Lethal Vapors

Whenever a creature enters, destroy it.
{0}: Destroy Lethal Vapors. You skip your next turn. Any player may activate this ability.

Leonin Arbiter

Players can't search libraries. Any player may pay {2} for that player to ignore this effect until end of turn.

Mana Cache

At the beginning of each player's end step, put a charge counter on Mana Cache for each untapped land that player controls.
Remove a charge counter from Mana Cache: Add {C}. Any player may activate this ability but only during their turn before the end step.