Singularity Rupture

Destroy all creatures, then any number of target players each mill half their library, rounded down.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Shield Broker

When this creature enters, put a shield counter on target noncommander creature you don't control. You gain control of that creature for as long as it has a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Siren of the Silent Song

Flying
Inspired — Whenever this creature becomes untapped, each opponent discards a card, then each opponent mills a card.

Herald of Secret Streams

Creatures you control with +1/+1 counters on them can't be blocked.

The Water Crystal

Blue spells you cast cost {1} less to cast.
If an opponent would mill one or more cards, they mill that many cards plus four instead.
{4}{U}{U}, {T}: Each opponent mills cards equal to the number of cards in your hand.

Gríma Wormtongue

Your opponents can't gain life.
{T}, Sacrifice another creature: Target player loses 1 life. If the sacrificed creature was legendary, amass Orcs 2.

Gríma, Saruman's Footman

Gríma can't be blocked.
Whenever Gríma deals combat damage to a player, that player exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Overture

Target opponent mills half their library, rounded down. (Then exile this card. You may play the land later from exile.)

Jidoor, Aristocratic Capital

Jidoor, Aristocratic Capital // Overture

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Danny Pink

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Creatures you control have "Whenever one or more counters are put on this creature for the first time each turn, draw a card."

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Lo and Li, Royal Advisors

Whenever an opponent discards a card or mills one or more cards, put a +1/+1 counter on each Advisor you control.
{2}{U/B}: Target player mills four cards. (They put the top four cards of their library into their graveyard.)

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Oppression

Whenever a player casts a spell, that player discards a card.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Lyla, Holographic Assistant

Whenever you draw a card, put a +1/+1 counter on target creature.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)