msem-instigator

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.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Whenever Aleud Blademaster becomes blocked, it gains double strike until end of turn.

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.

Aleud Scorn deals 3 damage to target creature.
At the beginning of your upkeep, you may exile Aleud Scorn from your graveyard. If you do, add {R}{R}.

Harmony — Warriors you control get +1/+0 and gain menace until end of turn.
Whenever Aleud Warcaller attacks, harmonize. (Trigger up to one harmony of a permanent you 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.

[+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.

When All-Blossom Memorial enters, scry 1.
Prismatic — Whenever you cast a multicolored spell, you gain 1 life.
{T}: Add one mana of any color.

If a creature would die this turn, exile it instead.
All-Consuming Fire deals 4 damage to each creature.

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.)

Whenever Almgrove Bladesinger attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Target creature can't block this turn.

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.”)

({T}: Add {G} or {W}.)
Alpine Meadow enters tapped.

Alquyut Mount can't attack or block alone.

As Alratha, Pearl of the Sand Sea enters, you may have an opponent investigate. If you don't, it enters tapped.
{T}: Add {U}.
{1}{U}, {T}: Investigate.

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.

Altar of Adversity enters tapped.
{T}: Add {B}.
{T}: Add {R} or {W}. Altar of Adversity doesn't untap during your next untap step unless you control an Angel creature.

Altar of Chaos enters tapped.
{T}: Add {R}.
{T}: Add {G} or {U}. Altar of Chaos doesn't untap during your next untap step unless you control an Angel creature.