msem-instigator

[+1]: Until end of turn, All-Enduring Mafua becomes a 5/5 Cat Warrior creature with lifelink and indestructible. (He doesn't lose loyalty while he's not a planeswalker.)
[–2]: Exile target creature.
[–X]: Return each creature card with mana value X from your graveyard to your hand.

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

[+1]: Create a 1/1 blue Merfolk creature token with “When this creature dies, draw a card, then discard a card.”
[–1]: Target creature gets -2/-0 until your next upkeep and attacks during its controller's next turn if able.
[–7]: You get an emblem with “Creatures your opponents control get -4/-0 and attack each turn if able.”

You gain 4 life. Then if you have more life than an opponent, draw 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.

This spell costs {1} less to cast for each artifact you control.
Draw two cards.

Target opponent loses 2 life and you gain 2 life. If you control a Wizard, instead that player loses 4 life and you gain 4 life.

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 Ambassador blocks or becomes blocked, you may untap target creature and remove it from combat.

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

First strike
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Almgrove Champion can only attack or block alone.

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.

When Almgrove Librarian enters, look at the top card of each of your libraries, then for each of those cards, put it on the top or bottom of one of your libraries.

When Almgrove Performer enters, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — You gain 3 life.

Defender
Whenever you cast an instant or sorcery spell, you may untap Almgrove Sentinel.
{T}: Almgrove Sentinel deals 1 damage to any target.

Whenever Almgrove Spellblade attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Exile the top two cards of your library. Until end of turn, you may play cards exiled by Almgrove Spellblade.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Enchanted creature loses all abilities except for mana abilities.

Whenever a nontoken creature you control dies, create a 1/1 black Spirit creature token with flying.
[+1]: Each opponent loses 2 life and you gain 2 life.
[–2]: You may sacrifice a creature. When you do, destroy target nonland permanent.

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.