Rotating Fireplace

This artifact enters tapped with a time counter on it.
{T}: Add an amount of {C} equal to the number of time counters on this artifact.
{4}, {T}: Time travel. Activate only as a sorcery. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter.)

The Wedding of River Song

Draw two cards, then you may exile a nonland card from your hand with a number of time counters on it equal to its mana value. Then target opponent does the same. Cards exiled this way that don't have suspend gain suspend.
Time travel. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter.)

Time Beetle

Skulk (This creature can't be blocked by creatures with greater power.)
Parallel Universe — Whenever this creature deals combat damage to a player, time travel. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter.)

Killer

Killer deals 3 damage to target creature and each other creature that shares a creature type with it.

Coward

Target creature can't block this turn and becomes a Coward in addition to its other types until end of turn.
Time travel.

Coward // Killer

The Tenth Doctor

Allons-y! — Whenever you attack, exile cards from the top of your library until you exile a nonland card. Put three time counters on it. If it doesn't have suspend, it gains suspend.
Timey-Wimey — {7}: Time travel three times. Activate only as a sorcery. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter. Then do it two more times.)

The Eleventh Doctor

I. AM. TALKING! — Whenever The Eleventh Doctor deals combat damage to a player, you may exile a card from your hand with a number of time counters on it equal to its mana value. If it doesn't have suspend, it gains suspend.
{2}: Target creature with power 3 or less can't be blocked this turn.

Sword Coast Sailor

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, this creature can't be blocked this turn."

Flaming Fist

Commander creatures you own have "Whenever this creature attacks, it gains double strike until end of turn."

The Parting of the Ways

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Exile the top five cards of your library. For each nonland card exiled this way, put a number of time counters on that card equal to its mana value. If it doesn't have suspend, it gains suspend.
II — Time travel, then time travel.
III — For each opponent, destroy up to one target artifact that player controls.

Amy Pond

Partner with Rory Williams (When this creature enters, target player may put Rory into their hand from their library, then shuffle.)
Whenever Amy Pond deals combat damage to a player, choose a suspended card you own and remove that many time counters from it.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Omnispell Adept

{2}{U}, {T}: You may cast an instant or sorcery spell from your hand without paying its mana cost.

All of History, All at Once

Time travel. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter.)
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Wibbly-wobbly, Timey-wimey

Time travel. (For each suspended card you own and each permanent you control with a time counter on it, you may add or remove a time counter.)
Draw a card.

Rory Williams

Partner with Amy Pond
First strike, lifelink
The Last Centurion — When you cast this spell from anywhere other than exile, exile it with three time counters on it. It gains suspend. Then investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")