Impossible Girl — If Clara Oswald is your commander, choose a color before the game begins. Clara Oswald is the chosen color.
If a triggered ability of a Doctor you control triggers, that ability triggers an additional time.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Whenever a creature an opponent controls attacks one of your opponents, double its power until end of turn.
: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, goad up to X target creatures your opponents control.

Whenever a player casts a spell, you may put a +1/+1 counter on this creature.
At the beginning of your upkeep, you may move any number of +1/+1 counters from this creature onto other creatures.

Return all creature and planeswalker cards with mana value X or less from your graveyard to the battlefield. Exile Ascend from Avernus.

Search your library for a Demon card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for any card, put it into your hand, then shuffle.

(: Add .)

When Horn of Gondor enters, create a 1/1 white Human Soldier creature token.
, : Create X 1/1 white Human Soldier creature tokens, where X is the number of Humans you control.

Counter target spell.

Green spells you cast cost less to cast.

+1: Discard a card. If a red card is discarded this way, Chandra deals 4 damage to any target.
−2: Each player discards their hand, then draws three cards.
−7: Cast any number of red instant and/or sorcery cards from your graveyard without paying their mana costs.

: Add one mana of any color. Put a nest counter on this creature.
, Sacrifice this creature: Create a 2/2 green Spider creature token with reach for each counter on this creature. Activate only as a sorcery.

Other outlaws you control have vigilance and haste. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
At the beginning of combat on your turn, you may have Treasures you control become 3/3 Construct Assassin artifact creatures in addition to their other types until end of turn.

Lightning Bolt deals 3 damage to any target.

You may pay rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield.
Each player sacrifices thirteen creatures of their choice.

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Flying, indestructible
Eternity Gate — Whenever this Vehicle attacks, mill three cards. For each creature card milled this way, create a 2/2 black Necron Warrior artifact creature token.
Crew 4 (Tap any number of creatures you control with total power 4 or more: This Vehicle becomes an artifact creature until end of turn.)

Flying, ward
Channel — , Discard this card: Return target card from your graveyard to your hand.
Channel — , Discard this card: Return target creature to its owner's hand.

For each token you control, create a token that's a copy of that permanent.

Whenever Haliya or another creature or artifact you control enters, you gain 1 life.
At the beginning of your end step, draw a card if you've gained 3 or more life this turn.
Warp (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)