Overgrown Farmland

Overgrown Farmland enters tapped unless you control two or more other lands.
{T}: Add {G} or {W}.

Sarah Jane Smith

Whenever you cast a historic spell, investigate. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic. To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Doctor's companion (You can have two commanders if the other is the Doctor.)

K-9, Mark I

Negative — As long as K-9, Mark I is untapped, other legendary creatures you control have ward {1}.
Affirmative — {1}{U}, {T}: Target legendary creature can't be blocked this turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Gallifrey Stands

When Gallifrey Stands enters, return all Doctor cards from your graveyard to your hand.
At the beginning of your upkeep, you may put a Doctor creature card from your hand onto the battlefield. Then if you control thirteen or more Doctors, you win the game.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

The Five Doctors

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Search your library and/or graveyard for up to five Doctor cards, reveal them, and put them into your hand. If you search your library this way, shuffle. If this spell was kicked, put those cards onto the battlefield instead of putting them into your hand.

Day of Destiny

Legendary creatures you control get +2/+2.

Traverse Eternity

Draw cards equal to the highest mana value among historic permanents you control. (Artifacts, legendaries, and Sagas are historic.)

Sungrass Prairie

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.

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.)

Time Lord Regeneration

Until end of turn, target Time Lord you control gains "When this creature dies, reveal cards from the top of your library until you reveal a Time Lord creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order."

Heroes' Podium

Each legendary creature you control gets +1/+1 for each other legendary creature you control.
{X}, {T}: Look at the top X cards of your library. You may reveal a legendary creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Banish to Another Universe

Affinity for historic permanents (This spell costs {1} less to cast for each artifact, legendary, and/or Saga permanent you control.)
When Banish to Another Universe enters, exile target nonland permanent an opponent controls until Banish to Another Universe leaves the battlefield.

Heroic Intervention

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

Wedding Ring

When Wedding Ring enters, if it was cast, target opponent creates a token that's a copy of it.
Whenever an opponent who controls an artifact named Wedding Ring draws a card during their turn, you draw a card.
Whenever an opponent who controls an artifact named Wedding Ring gains life during their turn, you gain that much life.

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.)

Bard Class

(Gain the next level as a sorcery to add its ability.)
Legendary creatures you control enter with an additional +1/+1 counter on them.
{R}{G}: Level 2
Legendary spells you cast cost {R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
{3}{R}{G}: Level 3
Whenever you cast a legendary spell, exile the top two cards of your library. You may play them this turn.

Reverse the Polarity

Choose one —
• Counter all other spells.
• Switch each creature's power and toughness until end of turn.
• Creatures can't be blocked this turn.

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

The Girl in the Fireplace

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 1/1 white Human Noble creature token with vanishing 3 and "Prevent all damage that would be dealt to this creature."
II — Create a 2/2 white Horse creature token with "Doctors you control have horsemanship." (They can't be blocked except by creatures with horsemanship.)
III — Whenever a creature you control deals combat damage to a player this turn, time travel.

Explore

You may play an additional land this turn.
Draw a card.

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.

Susan Foreman

If you would planeswalk, instead look at the top two cards of your planar deck, put one on the bottom of your planar deck and the other on top, then planeswalk.
{T}: Add {G}.
Doctor's companion (You can have two commanders if the other is the Doctor.)