msem-instigator

Flying, ward {2}
Whenever you cast a noncreature spell, choose up to one target creature. If that spell's mana value is greater than that creature's power, put +1/+1 counters on it equal to the difference.

Whenever Wadepool Frog attacks, it gains flying until end of turn.

When Hollowflesh Ghoul dies, create a 1/1 black Skeleton creature token.

Instant and sorcery spells you control have leitmotif. (Exile that spell as it resolves if you cast it from your hand. When you next cast a spell that shares a color with that card, you may cast it from exile without paying its mana cost.)

Whenever one or more creatures you control deal combat damage to a player, that player discards a card. Then that player may discard another card. If they don't, create two 2/1 black Nightmare creature tokens with “This creature can't block.”
Fleeting {1}{B}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Trample
{1}, Discard Shifting Brute: Add one mana of any color. Scry 1.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Paygan Archer dies, it deals damage to target player or planeswalker equal to its power.

Vigilance
{3}{W}, {T}: Tap target creature. This ability costs {3} less to activate as long as J-7 Freeze Frame is a creature.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

{T}, Sacrifice Decrepit Crags: Search your library for a Swamp or Mountain card and put it onto the battlefield tapped, then shuffle.

Whenever a storied permanent you control enters, you gain 1 life and each opponent loses 1 life. (Enchantments and legendary permanents are storied.)

Runewart Hog has hexproof as long as it has a +1/+1 counter on it.

I, II — Draw a card.
Discovery — Noncreature spells you cast cost {1} less to cast.

{T}: Add {C}.
When Heavenly Temple enters, target creature gains flying until end of turn.
{2}: Return Heavenly Temple from the battlefield to its owner's hand.

Spells your opponents cast that target Sheltered Snowman cost {2} more to cast.
Whenever you cast a spell from exile, put a +1/+1 counter on Sheltered Snowman. It can't be blocked this turn.

Flying
Whenever you attack with two or more creatures with flying, each opponent discards a card.

Target creature attacks or blocks this turn if able.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

{T}: Add {C}.
{T}: Add {G}, {U}, or {R}. You can't spend this mana to cast a monocolored spell.

When Judge of Clans enters, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature.” attached to target creature.)
{T}: Add one mana of any color.

Harmony — Draw a card, then discard a card.
Whenever Dramatic Artist attacks, harmonize. (Trigger up to one harmony of one permanent you control.)

Reach
Towering Silkweaver can block an additional creature each combat.

Lifelink
Mirage {1}{W} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Whenever this creature enters or attacks, you may put a creature card with mana value 2 or less from your hand onto the battlefield. If you do, draw a card. Sacrifice that creature at the beginning of the next end step.
If a creature would enter under your control during combat on your turn, that creature enters tapped and attacking.

{T}: Add {C}.
{1}, {T}: Add {U}{B}.

Flash
Motivate 7 (When this creature enters, you may motivate target creature with less power than this by putting seven +1/+1 counters on it.)

Enchant land
Enchanted land loses all land types, has “{T}: Add {C}”, and loses all other abilities.