msem-instigator

Flying
When Sha Long enters, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

Whenever Shah's Caravan attacks, creatures you control get +1/+1 until end of turn. If you control three or more Satrapies, creatures you control can't be blocked by creatures with power 2 or less this turn.
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

When Shardsong Seedling enters, conjure two cards named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When this creature enters, draw a card, then put a creature you control on top of its owner's library.

Siege Ent can't be blocked by creatures with power 2 or less as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Sire of the Shapeless costs {3} less to cast as long as you control three or more creatures.
Trample, haste
{G}, Reveal Sire of the Shapeless from your hand: Create a 1/1 colorless Human creature token. Shuffle Sire of the Shapeless into your library. Activate only as a sorcery.

When Sire of the Wild enters, reveal the top four cards of your library. You may put a creature card from among them onto the battlefield. Shuffle the rest into your library.

Deathtouch
When Slum Scrounger enters, put up to two target creature cards in your graveyard on top of your library in any order.

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.

Trample
Whenever a creature dealt damage by Sovereign of Old Lovi this turn dies, put a +1/+1 counter on Sovereign of Old Lovi.

Steel Hunter can't attack unless you control three or more other artifacts.

Trample

When Stonefall Golem leaves the battlefield, destroy target permanent.

Strider Engine enters tapped and with a -1/-1 counter on it unless you spent at least three colors of mana to cast it.

Exile up to one target artifact or enchantment.
Coalesce {5}{G} (You may cast this from your graveyard for {5}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Menace (This creature can't be blocked except by two or more creatures.)
Civilized — Whenever Subjugator of Empires attacks, if you control an artifact, a creature, and an enchantment, each opponent discards a card, sacrifices a creature, and loses 3 life.

Reach
Whenever another creature enters, untap Sylvan Subversive.

Flying
When Syrina, the Dragon Queen enters, gain control of target nonland permanent for as long as you control Syrina, the Dragon Queen.
{2}{U}: Exile Syrina, the Dragon Queen. Return her to the battlefield at the beginning of the next end step.

When Tantalizing Glutton enters, create a green Aura Curse enchantment token named Just Out of Reach attached to target player. The token has enchant player and “At the beginning of each of enchanted player's opponents' upkeeps, if that player doesn't control a Food, they create a Food token.”

Hexproof

Defender
Whenever another creature deals damage to Temperate Gazebo, you gain 3 life.

Defender
Other untapped creatures you control get +0/+1.
Each other creature you control can block an additional creature each combat.

Bulwark — When Tharanos' Legion enters, draw a card for each creature you control with toughness 4 or greater.

{5}{U}{U}: Thassa's Tidebringer can't be blocked this turn. This ability costs {1} less to activate for each creature you control with a counter on it.

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of each combat, you may tap or untap another target nonland permanent.
{2}{U}: Create a 1/1 blue Merfolk Rogue creature token with “{T}: Draw a card, then discard a card.”