Flying
Whenever Molten Slagmaw enters or attacks, each opponent sacrifices an artifact or nonbasic land.

Cast this spell only during your turn.
Target creature gets +2/+0 and gains haste until end of turn. If it's attacking, instead it gets +2/+0 and gains trample until end of turn.
Flashback {1}{R}

Target creature gains first strike and gets +X/+0 until end of turn, where X is your devotion to red.

Mundaq, Unlikely Savior can't be blocked by creatures whose power and toughness are equal.
{1}{W}, Return another creature you control to its owner's hand: Put a +1/+1 counter on Mundaq.

As an additional cost to cast this spell, discard a card.
Draw two cards.

Creatures you control get +2/+0 until end of turn. Up to one target Elemental you control gains first strike until end of turn.

[+1]: Exile the top card of your library. You may play it this turn. If that card doesn't share a name with a permanent you control or a card in your graveyard, add {R}{R}.
[–2]: Gain control of target creature until end of turn. Untap that creature. It gains haste and menace until end of turn.
[–6]: You get an emblem with “Whenever you amp it up, this emblem deals 2 damage to any target.”

Flash
When Omen of Storms enters, discard a card, then draw two cards.
{2}{R}, Sacrifice Omen of Storms: Scry 2.

Create three 1/1 red and green Elemental creature tokens.

Flying, haste
As an additional cost to cast spells with flashback, you may pay {1}{R}. When you do, return Opal-Eye Phoenix from your graveyard to the battlefield.

Enchant creature
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Karda.
Whenever you sacrifice Ordeal of Karda, creatures you control get +2/+0 until end of turn.

Whenever you cast an instant or sorcery spell, you may have target creature you control dare X and gain flying until end of turn, where X is that spell's mana value.

Create a token that's a copy of target creature you control, except it has haste. Sacrifice it at the beginning of the next end step. If {G} was spent this spell, the token must be blocked each combat this turn if able. If {B} was spent to cast this spell, the token gains deathtouch.

At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, Peaktop Predator deals 2 damage to target player or planeswalker.

Haste
Whenever Penrath Firearm attacks, create a colorless Equipment artifact token with “Equipped creature gets +2/+0” and equip {2} attached to target attacking creature.

When Pensive Caldera enters, you may discard a card. If you do, draw a card.
{T}: Add {R}. Spend this mana only to cast artifact, instant, or sorcery spells.

Trample
Petros's power is equal to your devotion to red.
Whenever Petros deals combat damage to a player, create an X/X colorless enchantment artifact creature token named Follower, where X is the amount of damage dealt.

When Photonic Cobra dies, create a 1/1 red and green Elemental creature token.

Exile the top two cards of your library. Until the end of your next turn, you may play those cards. Cards exiled this way cost {2} less to cast if they're instants, sorceries, or Elementals.

Flying, haste
When Plasmana Hellkite enters, it deals 2 damage to any target and 1 damage to any other target.

As Prodigious Hater enters, look at an opponent's hand, then choose a nonland card name.
Whenever an opponent casts a spell with the chosen name, Prodigious Hater deals 3 damage to that player.

Destroy target artifact. Pull the Wires deals 2 damage to that artifact's controller.

If you control three or more enchantments, damage dealt by sources you control this turn can't be prevented.
Punishment from Nyx deals 2 damage to any target.

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
You choose which creatures block this turn and how those creatures block.

Flying
Solidarity
Whenever Pyrewing Penancer attacks, it deals damage equal to its power to each opponent.