Aberrant Mind Sorcerer

Psionic Spells — When Aberrant Mind Sorcerer enters the battlefield, choose target instant or sorcery card in your graveyard, then roll a d20.
1—9 | You may put that card on top of your library.
10—20 | Return that card to your hand.

Vesuvan Doppelganger

You may have Vesuvan Doppelganger enter the battlefield as a copy of any creature on the battlefield, except it doesn't copy that creature's color and it has "At the beginning of your upkeep, you may have this creature become a copy of target creature, except it doesn't copy that creature's color and it has this ability."

Vesuvan Shapeshifter

As Vesuvan Shapeshifter enters the battlefield or is turned face up, you may choose another creature on the battlefield. If you do, until Vesuvan Shapeshifter is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."
Morph {1}{U}

Amulet of Vigor

Whenever a permanent enters the battlefield tapped and under your control, untap it.

Adrix and Nev, Twincasters

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
If one or more tokens would be created under your control, twice that many of those tokens are created instead.

Mythos of Illuna

Create a token that's a copy of target permanent. If {R}{G} was spent to cast this spell, instead create a token that's a copy of that permanent, except the token has "When this permanent enters the battlefield, if it's a creature, it fights up to one target creature you don't control."

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Quicksilver Amulet

{4}, {T}: You may put a creature card from your hand onto the battlefield.

Vesuvan Duplimancy

Whenever you cast a spell that targets only a single artifact or creature you control, create a token that's a copy of that artifact or creature, except it's not legendary.

Riku of Two Reflections

Whenever you cast an instant or sorcery spell, you may pay {U}{R}. If you do, copy that spell. You may choose new targets for the copy.
Whenever another nontoken creature enters the battlefield under your control, you may pay {G}{U}. If you do, create a token that's a copy of that creature.

Thran Temporal Gateway

{4}, {T}: You may put a historic permanent card from your hand onto the battlefield. (Artifacts, legendaries, and Sagas are historic.)

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.