msem-instigator

Monumental Siege deals 5 damage divided as you choose among any number of targets. Whenever a creature dealt damage this way this turn dies, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Flying
Whenever Scavenging Hilakites attacks, you may sacrifice another creature. When you do, Scavenging Hilakites deals damage equal to the sacrificed creature's power to any target.

Hexproof, reach

Reach, trample
Improve {1}{B/G} ({1}{B/G}: 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.)
Whenever one or more +1/+1 counters are put on Gorganith, Ruin Maw, you may search your library and/or graveyard for a creature card with mana value equal to or less than the number of +1/+1 counters on Gorganith and put it onto the battlefield. If you search your library this way, shuffle.

At the beginning of your end step, exile target permanent.
When Head of Ulko leaves the battlefield, return each other card exiled with it to the battlefield under your control.

Menace
When Graygulch Outcast dies, each opponent loses 3 life.

Flash
When Tenvilu, Earthen Warden enters, other creatures you control get +2/+2 and gain hexproof and indestructible until end of turn.

Equipped creature gets +0/+2 and has menace.
Equip {1}

Flying

Battalion — Whenever Battleborn Brute and at least two other creatures attack, Battleborn Brute gets +2/+2 until end of turn. Untap it.

(Add a quest counter as this enters. Sacrifice after 3.)
At the beginning of your end step, if you have more cards in hand than an opponent, add a quest counter.
1, 2 — Target opponent exiles the top card of their library. You may play that card for as long as it remains exiled. (You still pay its costs.)
3 — Create three Treasure tokens.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Manipulator of Waves attacks, mill three cards. Then create a 0/0 blue Elemental Serpent creature token with “This creature gets +1/+1 for each five cards in your graveyard.”

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Baptism by Fire deals 3 damage to target creature or planeswalker. If you're in a renaissance, Baptism by Fire deals 6 damage to that permanent instead.

Menace
Yaran's Enforcer gets +1/+1 as long as you foretold a card this turn.
Yaran's Enforcer gets +1/+1 as long as you cast a foretold spell this turn.

Enchant creature
Enchanted creature gets +1/+3.
{W}: Return Conviction to its owner's hand.

Mill four cards. You may put up to two cards from among the milled cards into your hand. Each player loses 2 life.

When Embrace Samang enters, put a charge counter on it for each color among permanents you control.
At the beginning of your first main phase, remove a charge counter from Embrace Samang. If you do, draw a card, then add one mana of any color.

Whenever Agent of Vitu-Ghazi deals combat damage to a player, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flying
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

Haste
Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)

Equipped creature gets +1/+1 and has flying.
Equip {2}

When Lunar Pact enters, target creature attacks during its controller's next combat if able.
Players can't untap more than two nonbasic permanents during their untap step.

Neo-Soul Nihilist has lifelink as long as it's attacking.
When Neo-Soul Nihilist is put into your graveyard from anywhere, you may pay 2 life. If you do, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

{1}, {T}, Move a -1/-1 counter from another creature onto Fervent Arbiter: Exile target creature you don't control until Fervent Arbiter leaves the battlefield.

Whenever you draw a card, put a quest counter on Fallback Plan.
Remove four quest counters from Fallback Plan and sacrifice it: Search your library for a card, put that card into your hand, then shuffle.