msem-instigator

Whenever Akoum Pathfinder attacks, create a 1/1 red Goblin creature token.
Other Goblins you control get +1/+0 and have haste.

Haste
{R}: Akoum Rockhurler gets +1/+0 until end of turn.
Whenever Akoum Rockhurler attacks, you may sacrifice a land. If you do, put two +1/+1 counters on Akoum Rockhurler.

Haste
Heroic — Whenever you cast a spell that targets Akroan Siege Captain, put a +1/+1 counter on each creature you control.

Flying
Whenever Albino Drake deals combat damage to an opponent, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When Alder Courtier dies, you gain 4 life.

At the beginning of your upkeep, you may sacrifice a Goblin. If you do, Alenian Boom Squad deals 2 damage to any target.

Other Goblins you control get +1/+0 and have menace.

Whenever a land you control enters, create a 1/1 red Elemental creature token. Then if you control three or more Elementals, exile Aleryn, Trapseeker, then return him to the battlefield transformed under his owner's control.

Menace
At the beginning of your upkeep, put a prize counter on target permanent you don't control.
Whenever a permanent with a prize counter on it is put into a graveyard from the battlefield, return it to the battlefield under your control.

When Allagras' Vanguard enters, create two 1/1 blue Merfolk creature tokens with “When this creature dies, draw a card, then discard a card”.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Alley Hunter has lifelink as long as it's blocked by a marked creature.

Alluring Rider must be blocked if able.
Attain {4}{G} ({4}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Lifelink
Whenever you cast a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Almgrove Ensemble deals 1 damage to target player or planeswalker.

Infamy 1 (Whenever this creature deals combat damage to a player, if it has no +1/+1 counters on it, put a +1/+1 counter on it and it becomes infamous.)
When Alpha Scout becomes infamous, create a 2/2 green Wolf creature token.

Double strike
Whenever an opponent casts a spell that targets you or a spell or permanent you control, Alrathan Outcast deals damage equal to twice its power to that player.
Alrathan Outcast gets +1/+1 for each Aura and Equipment you control.

Althestran Legionnaire gets +1/+1 for each Aura attached to it.

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)
{1}{W}: Target creature with a +1/+1 counter on it gains lifelink until end of turn.

First mate—At least half the cards in your starting deck are lands. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Trample
{1}, Discard a land card: Put a +1/+1 counter on Alvarez. He deals 1 damage to any target.

Sacrifice Amateur Auteur: Destroy target enchantment.

Reach
When Ambush Predator enters, you may return target Horror creature card from your graveyard to your hand.
When Ambush Predator dies, exile it and create a 3/2 green Horror creature token.

Trample
As long as it's an opponent's turn, Ambushing Alligator is a blue Bird with base power and toughness 1/1 and has flying and hexproof.

Lifelink
At the beginning of each end step, if you gained life this turn, you may pay {W/B}. If you do, create a 1/1 white Spirit creature token with flying.

When Aminatou's Adherent enters, judge target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)
Whenever you condemn a creature, creatures you control gain menace until end of turn.

Amleth, Royal Claimant can't be blocked by creatures with power 3 or less.
At the beginning of your end step, if you control three or more tapped creatures, create a 4/4 white Angel creature token with flying and vigilance. Otherwise, create a 1/1 white Soldier creature token.

Ammbradu Parasite gets +1/+1 as long as you control a Forest.
{4}{G}: Target creature must be blocked this turn if able.