Whenever a player casts a spell from their hand, Possibility Storm triggers, exiling the spell and allowing the player to reveal cards from the top of their library until they reveal a spell that shares a type with the exiled spell, and cast it without paying its mana cost.
If the player chooses to cast the spell, Void Mirror triggers, countering that spell since no colored mana was spent to cast it.

Counter all spells players cast from their hands

Lock

Void Mirror

Possibility Storm

Whenever a player casts a spell from their hand, Knowledge Pool triggers, exiling the spell and allowing the player to cast another card exiled by Knowledge Pool without paying its mana cost.
If the player chooses to cast a spell, Void Mirror triggers, countering that spell since no colored mana was spent to cast it.

Knowledge Pool

At the beginning of each draw step, Omen Machine prevents the active player from drawing a card, and causes them to exile the top card of their library, and cast that card if its a spell without paying its mana cost, or put it onto the battlefield if it's a land.
If an opponent casts a spell this way, Void Mirror triggers, countering that spell.

All spells opponents cast using Omen Machine are countered

Players can't draw cards

Omen Machine

Cast the artifact from your graveyard by paying {0} and 3 life.
Aetherflux Reservoir and Void Mirror trigger.
Resolve the Aetherflux Reservoir trigger, causing you to gain 1 life for each spell you've cast this turn.
Resolve the Void Mirror trigger, countering the artifact spell and returning it to your graveyard.
Repeat

Infinite damage

Infinite lifegain triggers

Infinite lifegain

Infinite storm count

Artifact Castable for {0} that survives

Noctis, Prince of Lucis

Aetherflux Reservoir

Cast any spell using only colorless mana.
Void Mirror triggers, exiling the spell and casting it from exile without paying its mana cost.
Repeat from step 2.

Infinite magecraft triggers

Guile

Whenever a player casts an instant or sorcery spell, Eye of the Storm triggers, exiling that spell and allowing the player to copy each spell exiled by Eye of the Storm and cast them from exile.
When the player casts the copies made by Eye of the Storm, Void Mirror triggers, countering those copies.

Combos with "Void Mirror"