Flame Elemental

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

Wildfire Emissary

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

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.

Suq'Ata Firewalker

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

Incinerate

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

Mist Dragon

{0}: Mist Dragon gains flying. (This effect lasts indefinitely.)
{0}: Mist Dragon loses flying. (This effect lasts indefinitely.)
{3}{U}{U}: Mist Dragon 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.)

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.)

Boomerang

Return target permanent to its owner's hand.

Armorer Guildmage

{B}, {T}: Target creature gets +1/+0 until end of turn.
{G}, {T}: Target creature gets +0/+1 until end of turn.

Bay Falcon

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Talruum Minotaur

Dream Fighter

Whenever Dream Fighter blocks or becomes blocked by a creature, Dream Fighter 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.)

Island

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.)

Burning Palm Efreet

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

Dissipate

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

Pyric Salamander

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

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.

Vaporous Djinn

Flying
At the beginning of your upkeep, Vaporous Djinn 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.)

Meddle

If target spell has only one target and that target is a creature, change that spell's target to another creature.

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.

Mountain

Subterranean Spirit

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