Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, this creature deals 1 damage to that player.
{3}{R}{R}: This creature gets +3/+3 and gains menace until end of turn.

Hissing Iguanar

Whenever another creature dies, you may have this creature deal 1 damage to target player or planeswalker.

Spitfire Lagac

Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Gev, Scaled Scorch

Ward—Pay 2 life.
Other creatures you control enter with an additional +1/+1 counter on them for each opponent who lost life this turn.
Whenever you cast a Lizard spell, Gev deals 1 damage to target opponent.

Iridescent Vinelasher

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.

Valley Flamecaller

If a Lizard, Mouse, Otter, or Raccoon you control would deal damage to a permanent or player, it deals that much damage plus 1 instead.

Viashino Pyromancer

When this creature enters, it deals 2 damage to target player or planeswalker.

Hired Claw

Whenever you attack with one or more Lizards, this creature deals 1 damage to target opponent.
{1}{R}: Put a +1/+1 counter on this creature. Activate only if an opponent lost life this turn and only once each turn.

Hearthborn Battler

Haste
Whenever a player casts their second spell each turn, this creature deals 2 damage to target opponent.

Kindlespark Duo

{T}: This creature deals 1 damage to target opponent.
Whenever you cast a noncreature spell, untap this creature.

Agate Instigator

Offspring {1}{R} (You may pay an additional {1}{R} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Magebane Lizard

Whenever a player casts a noncreature spell, this creature deals damage to that player equal to the number of noncreature spells they've cast this turn.

Scorch Spitter

Whenever this creature attacks, it deals 1 damage to the player or planeswalker it's attacking.