Toxic Iguanar

Toxic Iguanar has deathtouch as long as you control a green permanent. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Basking Rootwalla

{1}{G}: Basking Rootwalla gets +2/+2 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Drakewing Krasis

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.)

Undercity Necrolisk

{1}, Sacrifice another creature: Put a +1/+1 counter on Undercity Necrolisk. It gains menace until end of turn. Activate only as a sorcery. (It can't be blocked except by two or more creatures.)

Deathgazer

Whenever Deathgazer blocks or becomes blocked by a nonblack creature, destroy that creature at end of combat.

Whiptongue Hydra

Reach
When Whiptongue Hydra enters, destroy all creatures with flying. Put a +1/+1 counter on Whiptongue Hydra for each creature destroyed this way.

Lizard Blades

Double strike
Equipped creature has double strike.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Skitter of Lizards

Multikicker {1}{R} (You may pay an additional {1}{R} any number of times as you cast this spell.)
Haste
Skitter of Lizards enters with a +1/+1 counter on it for each time it was kicked.

Hall Monitor

Haste
{1}{R}, {T}: Target creature can't block this turn.

Spitfire Lagac

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

Lava Runner

Haste
Whenever Lava Runner becomes the target of a spell or ability, that spell or ability's controller sacrifices a land of their choice.

Underdark Explorer

Menace (This creature can't be blocked except by two or more creatures.)
When Underdark Explorer enters, you take the initiative.

Vivid Flying Fish

Vivid Flying Fish has flying as long as it's attacking. (It can't be blocked except by creatures with flying or reach.)

Bounding Krasis

Flash (You may cast this spell any time you could cast an instant.)
When Bounding Krasis enters, you may tap or untap target creature.

Lore Drakkis

Mutate {U/R}{U/R} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target instant or sorcery card from your graveyard to your hand.

Ludevic's Abomination

Ludevic's Test Subject

Defender
{1}{U}: Put a hatchling counter on Ludevic's Test Subject. Then if there are five or more hatchling counters on it, remove all of them and transform it.

Ludevic's Test Subject // Ludevic's Abomination

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.