msem-instigator

Primordial Slime can't be blocked by creatures with power 2 or less.
When Primordial Slime dies, you gain 5 life.
Foreshadow {5}{G}{G} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

When Rampaging Xiangshe enters, 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.”)
Each creature you control with a +1/+1 counter on it has trample.

Whenever Reclamation Grovesculptor enters or attacks, put a growth counter on target noncreature permanent. It becomes a colorless Forest land and loses all other card types and land types.

Deploy 3 (As this enters, you may tap any number of other creatures you control with total power 3 or more.)
When Relief Battalion enters deployed, draw a card.

Whenever Rhudai Swathcutter attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Reach
Risen Lumberknot gets +5/+5 as long as you control eight or more lands.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, untap all lands you control. This ability triggers only once each turn.

Changeling (This card is every creature type.)
This creature enters with four -1/-1 counters on it.
Whenever another creature you control enters, if that creature has greater power or toughness than this creature, remove a -1/-1 counter from this creature.

Trample
You may cast Sandswim Titan from exile. If you do, it enters with three +1/+1 counters on it.

Trample
When Scion of Flourishing enters, put a +1/+1 counter on each other creature you control. Those creatures gain trample until end of turn.
Whenever a Forest you control enters, you may aetherize Scion of Flourishing. (To aetherize, create a token that's a copy of it, then exile that token.)

Trample
Seasoned Adventurer enters with two +1/+1 counters if you control seven or more lands.

Trample
Shapen, Spiteful Creation must be blocked each combat if able.
The first time Shapen, Spiteful Creation would be dealt damage each turn, prevent that damage.

Resolute — Skerry Serpent must be blocked if able as long as its power is greater than its base power.

Trample

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.

Whenever Sower of Sabne's Harvest enters or attacks, align X, where X is your fealty to Forests. (Choose modes with total ★ less than or equal to the number of Forests you control. You may choose modes multiple times.)
• ★★ — Put a +1/+1 counter on target creature.
• ★★★ — Exile target artifact or enchantment.
• ★★★★★ — You gain 5 life.

Whenever Sower of Virulent Thoughts attacks, you may return a creature you control to its owner's hand. If you do, put a +1/+1 counter on target creature you control.

Flying
Creatures you control have “{T}: Add {C} or one mana of any color.”
{X}: The Finest Specimen gets +X/+X until end of turn.

Search your library for a card. You may cast it without paying its mana cost if it's a green creature or Revelation spell with mana value X or less. Then shuffle.
Coalesce {X}{X}{G}{G}{G}{G} (You may cast this from your graveyard for {X}{X}{G}{G}{G}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Trample
At the beginning of your upkeep, return another creature you control to its owner's hand.

Whenever Ujuraq, Elder Watcher enters or attacks, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Ujuraq gets +3/+3 and has trample as long as there are eight or more cards in your graveyard.

Colossal 3—{7}{G} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {7}{G} as a sorcery: Put three +1/+1 counters on it if it has none.)
When Voracious Asvosydna's colossal ability puts one or more counters on it, you gain 5 life.

Motivate 3 (When this creature enters, you may motivate target creature with lesser power than this by putting three +1/+1 counters on it.)
At the beginning of combat on your turn, you may have target creature you control gain vigilance until end of turn.

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
You may cast creature and enchantment spells as though they had flash.
Whenever another creature or enchantment you control enters, you gain 1 life.

Flying, lifelink
Whenever Shioki, Imperial Heir attacks, exile any number of other target nonland permanents you control, then return those cards to the battlefield under their owner's control.