Flame Elemental

{R}, {T}, Sacrifice this creature: It deals damage equal to its power to target creature.

Jolt

You may tap or untap target artifact, creature, or land.
Draw a card at the beginning of the next turn's upkeep.

Island

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Mist Dragon

{0}: This creature gains flying. (This effect lasts indefinitely.)
{0}: This creature loses flying. (This effect lasts indefinitely.)
{3}{U}{U}: This creature phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)

Harmattan Efreet

Flying
{1}{U}{U}: Target creature gains flying until end of turn.

Boomerang

Return target permanent to its owner's hand.

Subterranean Spirit

Protection from red
{T}: This creature deals 1 damage to each creature without flying.

Azimaet Drake

Flying
{U}: This creature gets +1/+0 until end of turn. Activate only once each turn.

Pyric Salamander

{R}: This creature gets +1/+0 until end of turn. Sacrifice this creature at the beginning of the next end step.

Incinerate

Incinerate deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.

Burning Palm Efreet

{1}{R}{R}: This creature deals 2 damage to target creature with flying and that creature loses flying until end of turn.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Kaervek's Torch

As long as Kaervek's Torch is on the stack, spells that target it cost {2} more to cast.
Kaervek's Torch deals X damage to any target.

Suq'Ata Firewalker

This creature can't be the target of red spells or abilities from red sources.
{T}: This creature deals 1 damage to any target.

Wildfire Emissary

Protection from white
{1}{R}: This creature gets +1/+0 until end of turn.

Goblin Scouts

Create three 1/1 red Goblin Scout creature tokens with mountainwalk. (They can't be blocked as long as defending player controls a Mountain.)

Mountain

Bay Falcon

Teferi's Drake

Flying
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

Vaporous Djinn

Flying
At the beginning of your upkeep, this creature phases out unless you pay {U}{U}. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)

Dream Fighter

Whenever this creature blocks or becomes blocked by a creature, this creature and that creature phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

Dream Cache

Draw three cards, then put two cards from your hand both on top of your library or both on the bottom of your library.