Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Inspiring Refrain

Draw two cards. Exile Inspiring Refrain with three time counters on it.
Suspend 3—{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Plains

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.)

Forest

Sol Ring

Aeon Chronicler

Aeon Chronicler's power and toughness are each equal to the number of cards in your hand.
Suspend X—{X}{3}{U}. X can't be 0.
Whenever a time counter is removed from this card while it's exiled, draw a card.

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.

Graham O'Brien

Paradox — Whenever you cast a spell from anywhere other than your hand, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Doctor's companion (You can have two commanders if the other is the Doctor.)

Ancestral Vision

Suspend 4—{U} (Rather than cast this card from your hand, pay {U} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Target player draws three cards.

Island

Command Tower

Clockspinning

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Choose a counter on target permanent or suspended card. Remove that counter from that permanent or card or put another of those counters on it.

Jhoira's Timebug

{T}: Choose target permanent you control or suspended card you own. If that permanent or card has a time counter on it, you may remove a time counter from it or put another time counter on it.