Dark Impostor

{4}{B}{B}: Exile target creature and put a +1/+1 counter on Dark Impostor.
Dark Impostor has all activated abilities of all creature cards exiled with it.

Faerie Impostor

Flying
When Faerie Impostor enters, sacrifice it unless you return another creature you control to its owner's hand.

Vent Sentinel

Defender
{1}{R}, {T}: Vent Sentinel deals damage to target player or planeswalker equal to the number of creatures you control with defender.

Council's Deliberation

Draw a card.
Whenever you scry, if you control an Island, you may exile Council's Deliberation from your graveyard. If you do, draw a card.

Fear of Impostors

Flash
When Fear of Impostors enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Council's Judgment

Will of the council — Starting with you, each player votes for a nonland permanent you don't control. Exile each permanent with the most votes or tied for most votes.

A Killer Among Us

When A Killer Among Us enters, create a 1/1 white Human creature token, a 1/1 blue Merfolk creature token, and a 1/1 red Goblin creature token. Then secretly choose Human, Merfolk, or Goblin.
Sacrifice A Killer Among Us, Reveal the creature type you chose: If target attacking creature token is the chosen type, put three +1/+1 counters on it and it gains deathtouch until end of turn.

Illicit Masquerade

Flash
When Illicit Masquerade enters, put an impostor counter on each creature you control.
Whenever a creature you control with an impostor counter on it dies, exile it. Return up to one other target creature card from your graveyard to the battlefield.

Venture Forth

Exile cards from the top of your library until you exile a land card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Exile Venture Forth with three time counters on it.
Suspend 3—{1}{G}

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")