Mirri the Cursed

Flying, first strike, haste
Whenever Mirri the Cursed deals combat damage to a creature, put a +1/+1 counter on Mirri the Cursed.

Glissa Sunseeker

First strike
{T}: Destroy target artifact if its mana value is equal to the amount of unspent mana you have.

Dross Hopper

Sacrifice a creature: Dross Hopper gains flying until end of turn.

Plummet

Fallen Angel

Flying
Sacrifice a creature: Fallen Angel gets +2/+1 until end of turn.

Vampire Nighthawk

Nature's Way

Target creature you control gains vigilance and trample until end of turn. It deals damage equal to its power to target creature you don't control.

Jump

Target creature gains flying until end of turn.

Leap

Target creature gains flying until end of turn.
Draw a card.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Springing Tiger

Threshold — Springing Tiger gets +2/+2 as long as seven or more cards are in your graveyard.

Bounding Krasis

Flash (You may cast this spell any time you could cast an instant.)
When Bounding Krasis enters the battlefield, you may tap or untap target creature.

Rayami, First of the Fallen

If a nontoken creature would die, exile that card with a blood counter on it instead.
As long as an exiled creature card with a blood counter on it has flying, Rayami, First of the Fallen has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Bounding Wolf

Soaring Seacliff

Soaring Seacliff enters the battlefield tapped.
When Soaring Seacliff enters the battlefield, target creature gains flying until end of turn.
{T}: Add {U}.

Precipitous Drop

Enchant creature
When Precipitous Drop enters the battlefield, venture into the dungeon. (Enter the first room or advance to the next room.)
Enchanted creature gets -2/-2. It gets -5/-5 instead as long as you've completed a dungeon.

Elfhame Wurm

Gurmag Swiftwing

Tragic Fall

Target creature gets -3/-3 until end of turn.
Hellbent — That creature gets -13/-13 until end of turn instead if you have no cards in hand.

Neoform

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield with an additional +1/+1 counter on it, then shuffle.

Nighthawk Scavenger

Flying, deathtouch, lifelink
Nighthawk Scavenger's power is equal to 1 plus the number of card types among cards in your opponents' graveyards.

Vault Skyward

Target creature gains flying until end of turn. Untap it.

Nightveil Predator

Flying, deathtouch
Hexproof (This creature can't be the target of spells or abilities your opponents control.)