Stigma Lasher

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever Stigma Lasher deals damage to a player, that player can't gain life for the rest of the game.

Countryside Crusher

At the beginning of your upkeep, reveal the top card of your library. If it's a land card, put it into your graveyard and repeat this process.
Whenever a land card is put into your graveyard from anywhere, put a +1/+1 counter on Countryside Crusher.

Aftershock

Destroy target artifact, creature, or land. Aftershock deals 3 damage to you.

Mogg Flunkies

Mogg Flunkies can't attack or block alone.

Slith Firewalker

Haste
Whenever Slith Firewalker deals combat damage to a player, put a +1/+1 counter on it.

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Cinder Cloud

Destroy target creature. If a white creature dies this way, Cinder Cloud deals damage to that creature's controller equal to the creature's power.

Convulsing Licid

{R}, {T}: Convulsing Licid loses this ability and becomes an Aura enchantment with enchant creature. Attach it to target creature. You may pay {R} to end this effect.
Enchanted creature can't block.

Blood Frenzy

Cast this spell only before the combat damage step.
Target attacking or blocking creature gets +4/+0 until end of turn. Destroy that creature at the beginning of the next end step.

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}.

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Breaking Point

Any player may have Breaking Point deal 6 damage to them. If no one does, destroy all creatures. Creatures destroyed this way can't be regenerated.

Figure of Destiny

{R/W}: Figure of Destiny becomes a Kithkin Spirit with base power and toughness 2/2.
{R/W}{R/W}{R/W}: If Figure of Destiny is a Spirit, it becomes a Kithkin Spirit Warrior with base power and toughness 4/4.
{R/W}{R/W}{R/W}{R/W}{R/W}{R/W}: If Figure of Destiny is a Warrior, it becomes a Kithkin Spirit Warrior Avatar with base power and toughness 8/8, flying, and first strike.