msem-instigator

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.
{3}{W}{U}: Tap target creature and put a +1/+1 counter on Solitary Guardian.

At the beginning of each player's upkeep, that player may pay {2} or 2 life. If they don't, they return a permanent they control to its owner's hand.

Whenever another creature you control enters, target opponent loses 1 life and you gain 1 life.
Sacrifice Somber River Bearer: Creatures you control gain indestructible until end of turn.

You may look at the top card of your library any time.
You may play lands from your graveyard and the top of your library.

Look at the top five cards of your library. You may reveal a nonland card from among them. If you do, put that card into your hand and cast a copy of it without paying its mana cost. Put the rest into your graveyard.

When Something in the Woods enters or at the beginning of your upkeep, Something in the Woods explores. If it explores a creature card, you may have it become a copy of that card. (It loses this ability. To explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)

When Somnambulance enters, each player conjures a card named Fatigue and puts it on top of their library. (It's a colorless sorcery that costs {2} with “Draw a card.”)
Whenever a player casts a spell named Fatigue, you may draw a card. If you do, you lose 1 life.

Enchant permanent
Enchanted permanent is a land with “{T}: Add {G}{W}{U}” and loses all other card types and abilities.
{1}, Discard Song of Shoals: Add one mana of any color. Scry 1.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Whenever a creature you control attacks alone, untap all lands you control.

As Sorcerous Spyglass enters, look at an opponent's hand, then choose any card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

[+1]: Draw a card. Each player loses 1 life.
[–2]: Create two 1/1 black Bat creature tokens with flying and lifelink.
[–3]: Target creature gets -13/-13 until end of turn. You control abilities of that creature that trigger this turn.

Flying, lifelink
Morph {4}{B}
When Soul Cajoler is turned face up, manifest the bottom card of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

{1}, {T}: Exile target card from a graveyard. Scry 1.
{T}, Exile Soul Gate: Exile all graveyards.

Destroy target creature unless its controller pays {3}.

Counter target creature spell unless its controller pays {2}.

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of your upkeep, exile up to one target nonland permanent you own. Return that card to your hand. If Soul Reader has two or more counters on it, you may instead return that card to the battlefield under your control.

Flying, trample, haste
{W}{U}{B}{R}{G}: Create a token that's a copy of another target creature except it's all colors and has haste.
{W}{U}{B}{R}{G}, Exile Soul of Iscathia from your graveyard: Create a token that's a copy of target creature except it's all colors and has haste.

Protection from colored spells
{5}{C}{C}: Exile target colored permanent.
{5}{C}{C}, Exile Soul of Muetar from your graveyard: Exile target colored permanent.

Tap two untapped creatures you control: Harmonize. (Trigger up to one harmony of one permanent you control.)
Harmony — Choose one —
• Soul of New Alores becomes a creature in addition to its other types until end of turn.
• Put two +1/+1 counters on target permanent.

Trample, haste
When Soul of the Mountain enters, if it isn't a token, for each two Mountains you control, create a token that's a copy of it.

Whenever another creature enters, you may gain 1 life.

Whenever you sacrifice a permanent, you may put a soul counter on Soul's Guidestone.
As long as there are five or more soul counters on Soul's Guidestone, it's a 6/6 Golem artifact creature with menace and vigilance.

{1}, {T}, Sacrifice Soul-Synthesizer: Look at the top seven cards of your library. You may reveal a card with an activated ability from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Soulblade enters, exile target creature card with mana value 3 or less from your graveyard.
Whenever equipped creature attacks, create a token that's a copy of a card exiled with Soulblade that's tapped and attacking. Exile the token at end of combat.
Equip {1}

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
When Soulbreaker of Mautakesh enters, target poisoned player sacrifices a creature.