msem-instigator

Whenever you cast a noncreature spell, put a +1/+1 counter on Adrift Surveyor.
Surpass {5}{U} ({5}{U}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Lifelink
Whenever an opponent loses life, you may pay {2}. If you do, choose one—
• That player discards a card.
• Put a +1/+1 counter on Adversary Ancestor.

Sacrifice a creature: Until end of turn, Advocate of Foibles gets +2/+0 and becomes a Demon in addition to its other types.
{1}{B}{G}: Amass Soldiers 1. (Put a +1/+1 counter on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

{1}{W}: Aegis Champion gains indestructible until end of turn.

First strike, menace
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of each combat, you may pay {1}. When you do, another target creature gains melee until end of turn. (If a creature has multiple instances of melee, each triggers separately.)

{1}{U}: Aeon's Hand Cutthroat can't be blocked this turn.

Flying, double strike

Flying
As long as Aerial Tactician is tapped, Soldiers you control get +0/+1.
As long as Aerial Tactician is untapped, Soldiers you control get +1/+0.

{T}, Discard a card: Draw a card from each of your libraries.
{1}{U}{R}, {T}, Discard your hand: Return each Study card from your graveyard to your hand.

Flying, first strike

Flying
Your opponents play with their hands revealed.
If an opponent would search their library for a card, you may have that player search their hand for that card instead.

Flying
Whenever Aether Crosser attacks, you may aetherize another target tapped creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)
Crew 1

When Aether Road Caravan enters, gain control of target nonland permanent with mana value 3 or less for as long as you control Aether Road Caravan.

Whenever a land you control enters, untap Ageless Wanderer.
{1}, {T}: Add one mana of any color.

Whenever a creature you control dies, put a +1/+1 counter on Agent of Andazir.

Flash
When Agent of Equilibrium enters, destroy target creature or planeswalker an opponent controls that was dealt damage this turn.

Deception {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Agent of Long Shadows deals combat damage to a player, you may put a Rogue card from your hand or graveyard onto the battlefield.

Menace, haste
Whenever Aiel's Fury attacks, scry 2, then reveal the top card of your library. Aiel's Fury gets +X/+0 until end of turn, where X is that card's mana value.

Rapport — Whenever Ainok Brushwacker and at least one other creature you control become tapped, Ainok Brushwacker gains first strike until end of turn.

Whenever Ainok Caretaker or another Hound you control attacks, untap that creature and it gets +1/+1 until end of turn.

Trample
Other Hounds you control get +1/+1 and have trample.

Whenever another creature named Ainok Pack you control enters, you gain 2 life.

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.

Aurashaper and Aura spells you cast cost {1} less to cast.

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