Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Alpine Moon

As Alpine Moon enters, choose a nonbasic land card name.
Lands your opponents control with the chosen name lose all land types and abilities, and they gain "{T}: Add one mana of any color."

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Crash Through

Creatures you control gain trample until end of turn. (Each of those creature can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Aria of Flame

When Aria of Flame enters, each opponent gains 10 life.
Whenever you cast an instant or sorcery spell, put a verse counter on Aria of Flame, then it deals damage equal to the number of verse counters on it to target player or planeswalker.

Renegade Tactics

Target creature can't block this turn.
Draw a card.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Phyresis

Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Mountain

Haggle

You may discard a card. If you do, draw a card. (Then exile this card. You may cast the creature later from exile.)

Merchant of the Vale

Merchant of the Vale // Haggle

Kiln Fiend

Whenever you cast an instant or sorcery spell, Kiln Fiend gets +3/+0 until end of turn.

Expedite

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

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Obsidian Charmaw

This spell costs {1} less to cast for each land your opponents control that could produce {C}.
Flying
When Obsidian Charmaw enters, destroy target nonbasic land an opponent controls.

Warlord's Fury

Creatures you control gain first strike until end of turn.
Draw a card.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.