msem-instigator

Codex — Leyran Alpha; Fungal Whomper; Plated Crusher; Towering Hydraffe; The Terror of Shady Cove. (As this enters, conjure its contents into a shuffled face-up additional library.)
When Mother of Monsters enters, you gain 6 life.
When Mother of Monsters dies, draw a card.

Shuffle your hand and graveyard into your library, then draw a card for each spell you cast this turn.

This creature gets +1/+0 and has indestructible as long as another Knight or Soldier entered under your control this turn.

You may sacrifice three Treasures rather than pay this spell's mana cost.
Flying, trample, haste

When Writhing Gateway enters, you may discard a card. If you do, create a 5/3 black Horror creature token.
{1}{B}{B}, Discard a card: Create a 5/3 black Horror creature token.

Sacrifice a creature. Draw cards equal to its power and gain life equal to its toughness. (Then exile this card. You may cast the creature later from exile.)

Flying
{1}, Sacrifice another creature: Regenerate target Vampire.

Whenever Merrow Legendmaker attacks, look at the top five cards of your library. You may reveal an Aura, Aurashaper, or Equipment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Wild Hermit dies, create a 2/2 white Cat creature token.
Revive—{3}{G}{G}, Sacrifice a creature. ({3}{G}{G}, Sacrifice a creature, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Vigilance
Whenever Disgruntled Student deals combat damage to a player, scry 2.

At the beginning of combat on each of your turns, you may sacrifice a land or exile a land card from your graveyard. If you do, create two 1/1 red Goblin creature tokens with haste. Exile those tokens at the beginning of the next end step.

Surveil 1, then draw a card. You lose 1 life.
Flashback—{B}, Sacrifice a creature. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Trample
Greypelt Ruffian gets +1/+1 as long as you control a storied permanent. (Enchantments and legendary permanents are storied.)

Enchant creature
When Sporegraft enters, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)
Enchanted creature has lifelink.

Reach
Spined Tarantula gets +1/+1 for each creature with flying your opponents control.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Crusher Beetle can't be blocked by more than one creature.

Ward—Pay 2 life.
Whenever another creature dies, put a hysteria counter on Mob of the End.
At the beginning of your first main phase, remove all hysteria counters from Mob of the End and add that much {R}.

When Marshal of Brethren enters, 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.)

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. You gain 2 life.

Volcanic Rain deals damage to target creature or planeswalker equal to the number of lands you control.

{4}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Choose two —
• Tap target creature.
• Untap target creature.
• Draw a card.

Haste
Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Bloodboil Harlequin desecrates a permanent, up to two target creatures can't block this turn.

Create a token that's a copy of target creature or land you control, except it has haste and “At the beginning of the end step, exile this permanent.” If a land you control was targeted this way, create two of those tokens instead.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)