Mandy Jurgens

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.)

"For a secret brotherhood, you certainly do get a lot of new recruits."
—Leonardo, to Ezio

Assassin Initiate

{1}: Assassin Initiate gains your choice of flying, deathtouch, or lifelink until end of turn.

{1}: This creature gains your choice of flying, deathtouch, or lifelink until end of turn.

The Hidden Ones were disciplined and patient, always waiting for the perfect moment to strike down their target and escape unnoticed.

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

Lydia Frye

Lydia Frye can't be blocked by creatures with power 3 or greater.
At the beginning of your end step, surveil X, where X is the number of tapped Assassins you control. (Look at the top X cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Cleopatra, Exiled Pharaoh

Allies — At the beginning of your end step, put a +1/+1 counter on each of up to two other target legendary creatures.
Betrayal — Whenever a legendary creature with counters on it dies, draw a card for each counter on it. You lose 2 life.

When Miku sings, it's her fans that feel heard.

Shelter

Target creature you control gains protection from the color of your choice until end of turn.
Draw a card.

Start the TARDIS

Surveil 2, then draw a card. You may planeswalk. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Jenny, Generated Anomaly

Double strike
Whenever Jenny deals combat damage to a player, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

"It's a juddering dimensional portal in a mirror in a Norwegian bedroom."
—The Thirteenth Doctor

Cursed Mirror

{T}: Add {R}.
As this artifact enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.