Altar of the Brood

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

The Fifth Doctor

Peaceful Coexistence — At the beginning of your end step, put a +1/+1 counter on each creature you control that didn't attack or enter this turn. Untap those creatures.

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.)

Teshar, Ancestor's Apostle

Flying
Whenever you cast a historic spell, return target creature card with mana value 3 or less from your graveyard to the battlefield. (Artifacts, legendaries, and Sagas are historic.)

Ellie and Alan, Paleontologists

{T}, Exile a creature card from your graveyard: Discover X, where X is the mana value of the exiled card. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Helga, Skittish Seer

Whenever you cast a creature spell with mana value 4 or greater, you draw a card, gain 1 life, and put a +1/+1 counter on Helga, Skittish Seer.
{T}: Add X mana of any one color, where X is Helga, Skittish Seer's power. Spend this mana only to cast creature spells with mana value 4 or greater or creature spells with {X} in their mana costs.

Peri Brown

The first historic spell you cast each turn has convoke. (Your creatures can help cast it. Each creature you tap while casting it pays for {1} or one mana of that creature's color.)
Doctor's companion (You can have two commanders if the other is the Doctor.)

Prop Room

Untap each creature you control during each other player's untap step.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Dazzling Theater

Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for {1} or one mana of that creature's color.)
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Dazzling Theater // Prop Room

The Night of the Doctor

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after II.)
I — Destroy all creatures.
II — Return target legendary creature card from your graveyard to the battlefield. Put your choice of a first strike, vigilance, or lifelink counter on it.

High Fae Trickster

Flash (You may cast this spell any time you could cast an instant.)
Flying
You may cast spells as though they had flash.

Desynchronization

Return each nonland permanent that's not historic to its owner's hand. (Artifacts, legendaries, and Sagas are historic.)

City of Death

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after VI.)
I — Create a Treasure token.
II, III, IV, V, VI — Create a token that's a copy of target non-Saga token you control.

Adric, Mathematical Genius

{2}{U}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
Ultimate Sacrifice — {1}{U}, Sacrifice Adric: Counter target activated or triggered ability.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Vrestin, Menoptra Leader

Flying
Vrestin enters with X +1/+1 counters on it.
When Vrestin enters, create X 1/1 green and white Alien Insect creature tokens with flying.
Whenever you attack with one or more Insects, put a +1/+1 counter on each of them.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.

The Myriad Pools

(Transforms from The Everflowing Well.)
{T}: Add {U}.
Whenever you cast a permanent spell using mana produced by The Myriad Pools, up to one other target permanent you control becomes a copy of that spell until end of turn.

The Everflowing Well

When The Everflowing Well enters, mill two cards, then draw two cards.
Descend 8 — At the beginning of your upkeep, if there are eight or more permanent cards in your graveyard, transform The Everflowing Well.

The Everflowing Well // The Myriad Pools

Terisian Mindbreaker

Whenever Terisian Mindbreaker attacks, defending player mills half their library, rounded up.
Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Mindcrank

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

Cloakwood Hermit

Commander creatures you own have "At the beginning of your end step, if a creature card was put into your graveyard from anywhere this turn, create two tapped 1/1 green Squirrel creature tokens."

Chimil, the Inner Sun

Spells you control can't be countered.
At the beginning of your end step, discover 5. (Exile cards from the top of your library until you exile a nonland card with mana value 5 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Raff Capashen, Ship's Mage

Flash
Flying
You may cast historic spells as though they had flash. (Artifacts, legendaries, and Sagas are historic.)

The Sixth Doctor

Time Lord's Prerogative — Whenever you cast a historic spell, copy it, except the copy isn't legendary. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic. A copy of a permanent spell becomes a token.)

Jace Reawakened

You can't cast Jace Reawakened during your first, second, or third turns of the game.
+1: Draw a card, then discard a card.
+1: You may exile a nonland card with mana value 3 or less from your hand. If you do, it becomes plotted.
−6: Until end of turn, whenever you cast a spell, copy it. You may choose new targets for the copy.

Romana II

Vigilance
{1}, {T}: Create a tapped token that's a copy of target token that entered this turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Alistair, the Brigadier

Whenever you cast a historic spell, create a 1/1 white Soldier creature token. (Artifacts, legendaries, and Sagas are historic.)
Whenever Alistair attacks, you may pay {8}. If you do, creatures you control get +X/+X until end of turn, where X is the number of historic permanents you control.