msem-instigator

Menace
Whenever a creature an opponent controls dies, 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.”)

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Heroic — Whenever you cast a spell that targets Aegis Hero, put a +1/+1 counter on Aegis Hero.

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

Flash
When you cast Aether Ascendant, you may have it become a copy of target instant or sorcery spell. If you do, choose new targets for it. (It won't enter.)

Spells you cast from anywhere other than your hand cost {1} less to cast.
Whenever an opponent casts a spell with the same name as a card they own in exile or in their graveyard, that player loses 1 life and you gain 1 life.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Aether Recoverer envisions a creature card, return target noncreature card from your graveyard to your hand.

Defender, reach
Aetherlock Effigy can block an additional creature each combat.
When Aetherlock Effigy dies, create two 1/1 black Bird creature tokens with flying.

Flash
When Aethermancer's Familiar enters, at the beginning of the next end step, you may aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

At the beginning of your end step, you lose 3 life unless you sacrifice a creature.

When Affluent Knight enters, recruit, then recruit again. (To recruit, create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

When Ageless Weaver enters, create a green Aura enchantment token named Years of Experience attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.”
Whenever an enchanted creature you control dies, create a 3/3 green Elemental creature token.

Deception {1}{B}
When Aguri, Shadow of Doubt enters, target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Ainok Alpha can't be blocked by more than one creature.
Other Hounds you control get +1/+1 and can't be blocked by more than one creature.

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

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

Menace
Whenever Akoum Trailblazer deals combat damage to a player, you may discard a card. If you do, draw a card.
Whenever you discard a card, you may pay {R}. If you do, create a 1/1 red Goblin creature token.

When Alaina enters, each opponent loses X life and you gain X life, where X is the number of Clerics you control.
{W}{B}, Pay 2 life: Return Alaina from your graveyard to your hand. Activate only if you have more life than your starting life total.

At the beginning of each upkeep, if no spells were cast last turn, create a 2/2 green Wolf creature token.
{3}{R/G}{R/G}: Albin, the Huntmaster and creature tokens you control get +2/+2 and gain trample until end of turn.

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.”)

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.

Menace
Whenever a creature blocks, put a -1/-1 counter on that creature at end of combat.
Creatures with -1/-1 counters on them can't block.

Menace
Whenever Algrin's Legacy becomes the target of a spell an opponent controls, that spell's controller loses 5 life unless they discard a card.

Lethal damage dealt to creatures is determined by their power rather than their toughness.