Two-Headed Cerberus

Double strike (This creature deals both first-strike and regular combat damage.)

Akroan Sergeant

First strike (This creature deals combat damage before creatures without first strike.)
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)

Ravaging Blaze

Ravaging Blaze deals X damage to target creature.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Ravaging Blaze also deals X damage to that creature's controller.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Circle of Flame

Whenever a creature without flying attacks you or a planeswalker you control, this enchantment deals 1 damage to that creature.

Senseless Rage

Enchant creature
Enchanted creature gets +2/+2.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Flame-Wreathed Phoenix

Flying
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When this creature enters, if tribute wasn't paid, it gains haste and "When this creature dies, return it to its owner's hand."

Thopter Engineer

When this creature enters, create a 1/1 colorless Thopter artifact creature token with flying.
Artifact creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Chandra's Outrage

Chandra's Outrage deals 4 damage to target creature and 2 damage to that creature's controller.

Chandra, Roaring Flame

+1: Chandra deals 2 damage to target player or planeswalker.
−2: Chandra deals 2 damage to target creature.
−7: Chandra deals 6 damage to each opponent. Each player dealt damage this way gets an emblem with "At the beginning of your upkeep, this emblem deals 3 damage to you."

Chandra, Fire of Kaladesh

Whenever you cast a red spell, untap Chandra.
{T}: Chandra deals 1 damage to target player or planeswalker. If Chandra has dealt 3 or more damage this turn, exile her, then return her to the battlefield transformed under her owner's control.

Chandra, Fire of Kaladesh // Chandra, Roaring Flame

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Bloodmark Mentor

Red creatures you control have first strike.

Mountain

Infectious Bloodlust

Enchant creature
Enchanted creature gets +2/+1, has haste, and attacks each combat if able.
When enchanted creature dies, you may search your library for a card named Infectious Bloodlust, reveal it, put it into your hand, then shuffle.

Chandra's Phoenix

Flying
Haste (This creature can attack and {T} as soon as it comes under your control.)
Whenever an opponent is dealt damage by a red instant or sorcery spell you control or by a red planeswalker you control, return this card from your graveyard to your hand.