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.

Fireglass Mentor

At the beginning of your second main phase, if an opponent lost life this turn, exile the top two cards of your library. Choose one of them. Until end of turn, you may play that card.

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.

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, Scaled Scorch deals 1 damage to target opponent.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Murderous Redcap

When Murderous Redcap enters, it deals damage equal to its power to any target.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)