Ayara's Oathsworn

Menace
Whenever Ayara's Oathsworn deals combat damage to a player, if it has fewer than four +1/+1 counters on it, put a +1/+1 counter on it. Then if it has exactly four +1/+1 counters on it, search your library for a card, put it into your hand, then shuffle.

War-Name Aspirant

Raid — War-Name Aspirant enters with a +1/+1 counter on it if you attacked this turn.
War-Name Aspirant can't be blocked by creatures with power 1 or less.

Thundering Raiju

Haste
Whenever Thundering Raiju attacks, put a +1/+1 counter on target creature you control. Then Thundering Raiju deals X damage to each opponent, where X is the number of modified creatures you control other than Thundering Raiju. (Equipment, Auras you control, and counters are modifications.)

Zoetic Cavern

{T}: Add {C}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

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.

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}.

Embodiment of Flame

Whenever a spell you control deals damage, put a flame counter on Embodiment of Flame.
{1}, Remove a flame counter from Embodiment of Flame: Exile the top card of your library. You may play that card this turn.

Flame Channeler

When a spell you control deals damage, transform Flame Channeler.

Flame Channeler // Embodiment of Flame

Bloodhall Ooze

At the beginning of your upkeep, if you control a black permanent, you may put a +1/+1 counter on Bloodhall Ooze.
At the beginning of your upkeep, if you control a green permanent, you may put a +1/+1 counter on Bloodhall Ooze.

Magus of the Moon

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Rigging Runner

First strike
Raid — Rigging Runner enters with a +1/+1 counter on it if you attacked this turn.

Flametongue Yearling

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Flametongue Yearling enters with a +1/+1 counter on it for each time it was kicked.
When Flametongue Yearling enters, it deals damage equal to its power to target creature.

The Autonomous Furnace

The Autonomous Furnace enters tapped.
{T}: Add {R}.
{1}{R}, {T}, Sacrifice The Autonomous Furnace: Draw a card.

Akroma, Angel of Fury

This spell can't be countered.
Flying, trample, protection from white and from blue
{R}: Akroma, Angel of Fury gets +1/+0 until end of turn.
Morph {3}{R}{R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Slumbering Dragon

Flying
Slumbering Dragon can't attack or block unless it has five or more +1/+1 counters on it.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Slumbering Dragon.

Valakut Stoneforge

Valakut Stoneforge enters tapped.
{T}: Add {R}.

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Voldaren Thrillseeker

Backup 2 (When this creature enters, put two +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)
{1}, Sacrifice this creature: It deals damage equal to its power to any target.

Falkenrath Exterminator

Whenever Falkenrath Exterminator deals combat damage to a player, put a +1/+1 counter on it.
{2}{R}: Falkenrath Exterminator deals damage to target creature equal to the number of +1/+1 counters on Falkenrath Exterminator.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.