msem-instigator

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Whenever Airam, Packleader becomes blocked, other creatures you control get +1/+1 until end of turn.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
When Aith Aera Sentinel enters, create a 1/1 green Elf creature token.

Whenever a creature token you control enters, put a +1/+1 counter on target creature you control.

Trample
Wanderlust — Whenever Akkrixian Assailants attacks, if you control four or more differently named lands, put a +1/+1 counter on it.

Untap target creature. It gets +1/+1 for each token you control until end of turn.

When Alder Courtier dies, you gain 4 life.

Aleud Beastmaster has frenzy X, where X is the number of unblocked attacking creatures you control. (Whenever it attacks and isn't blocked, it gets +X/+0 until end of turn.)

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Aleud Bladedancer has hexproof as long as it's attacking.

Enchant creature
Enchanted creature gets +2/+2 and has hexproof.
Sacrifice Aleud Grace: Enchanted creature gains indestructible until end of turn.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Aleud Pathfinder becomes blocked, untap up to two lands you control.

[+1]: Create a 1/1 green Saproling creature token. You gain 2 life.
[0]: Creature spells you cast this turn can't be countered. As they enter, they gain hexproof until your next turn.
[–2]: Create a green enchantment token named Survival with “You and other permanents you control have ward {1}.”

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Vanishing 2 (This permanent enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from All Who Wander, you gain 2 life and scry 1.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.
{1}{G}, Sacrifice Allure of the Woods: Draw a card.

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.)

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.

Trample
Whenever a creature attacks, Alpha Stag gets +2/+2 until end of turn.

Enchant land
Enchanted land has “{T}: Add one mana of any color.”
{3}, Sacrifice Alpha Trial: Conjure a card named Test Run into your hand. (It's a sorcery that costs {X}{G} with “Create an X/X green Mutant creature token. Draw a card.”)

Reach
Concord — Am'atambi's Fangs gets +1/+0 and has deathtouch as long as there are four or more card types among permanents you control.

Enchant creature
Enchanted creature gets +2/+2.
Whenever enchanted creature attacks, if it's a Scout, scry 2.

Flash (You may cast this spell any time you could cast an instant.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

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.

Reach, vigilance
When Amorphous Tyrant enters, another target creature you control deals damage equal to its power to target creature or planeswalker you don't control.
Evoke {G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

({T}: Add {G}.)
As Ancestral Glade enters, you may pay 1 life. If you don't, Ancestral Glade enters tapped.
Basic lands you control have “{T}: Add {G}.”

Whenever Ancient Durumderm attacks, you may return another creature you control to its owner's hand. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)