Plains

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.)

Take Up the Shield

Put a +1/+1 counter on target creature. It gains lifelink and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Luminous Rebuke

This spell costs {3} less to cast if it targets a tapped creature.
Destroy target creature.

Jem Lightfoote, Sky Explorer

Flying, vigilance
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Errant and Giada

Flash
Flying
You may look at the top card of your library any time.
You may cast spells with flash or flying from the top of your library.

Seachrome Coast

Seachrome Coast enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Seized from Slumber

Resolute Reinforcements

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, create a 1/1 white Soldier creature token.

Geyser Drake

Flying
During turns other than yours, spells you cast cost {1} less to cast.

Werefox Bodyguard

Flash
When Werefox Bodyguard enters, exile up to one other target non-Fox creature until Werefox Bodyguard leaves the battlefield.
{1}{W}, Sacrifice Werefox Bodyguard: You gain 2 life.

Brineborn Cutthroat

Flash (You may cast this spell any time you could cast an instant.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on this creature.

Eaten by Piranhas

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature loses all abilities and is a black Skeleton creature with base power and toughness 1/1. (It loses all other colors, card types, and creature types.)

Stoic Sphinx

Flash
Flying
Stoic Sphinx has hexproof as long as you haven't cast a spell this turn.

Plumecreed Escort

Flash
Flying
When Plumecreed Escort enters, target creature you control gains hexproof until end of turn.