msem-instigator

Whenever a land you control enters, choose one. If it doesn't share a name with another land you control, instead choose both—
• Create a 1/1 Scout creature token that's all colors.
• Put a +1/+1 counter on a creature you control.

Target creature you control fights another target creature. If either of those creatures would die this turn, exile it instead.

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{G}, Sacrifice Jade Vault Reclaimer: Destroy target artifact or enchantment.

{T}: Add {G}. If you control an attacking creature, add one mana of any color instead.

Reach (This creature can block creatures with flying.)
Whenever a creature you control enters for the first time each turn, untap Skittering Swarm. It gets +1/+1 until end of turn.

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

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever Wild Lifescale attacks, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Whenever one or more counters are put on a permanent you control for the first time each turn, create that many 1/1 green Squirrel creature tokens.
{1}{G}{W}, {T}: Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

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.)
Vigilance, lifelink
Whenever an opponent casts a spell, this permanent phases out until end of turn. (Treat it and anything attached to it as though they don't exist until end of turn.)

Flying
Whenever an opponent casts a spell, copy it. You may choose new targets for the copy.

When Grim Botanist enters, create a 1/1 green Saproling creature token.
Whenever a nontoken creature you control dies, populate. (Create a token that's a copy of a creature token you control.)

Whenever an artifact you control enters, look at the top card of your library. If that card's mana value is less than or equal to that artifact's mana value, you may reveal it and put that card into your hand. Otherwise, put it on the top or bottom of your library.

You may have Imaginative Dreamer enter as a copy of any creature on the battlefield. When it does, it stops being a copy.

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
{2}{W}{B}: Ishim's Meddling becomes a 4/4 Angel creature with flying and vigilance until end of turn.

Whenever Lackeybot deals damage to a player, choose an artifact card with mana value X or less at random, where X is the amount of damage dealt. You may create a token that's a copy of that card.

Whenever another creature you control dies, put a +1/+1 counter on Marshy Marauder.
When Marshy Marauder dies, create a 1/1 green Insect creature token for each counter on it.

Enchant player
Whenever one or more creatures attack enchanted player, their controller may sacrifice a creature. If they do, enchanted player loses 3 life, sacrifices a nonland permanent, and discards a card.

Flying
If a +1/+1 counter would be put on a creature you control, you may instead put your choice of a flying counter, a vigilance counter, or a trample counter on it.

When Sigiled Bulwark enters, search your library for a creature card and a noncreature card and reveal them. An opponent chooses one of those cards. Shuffle the chosen card into your library, then put the rest into your hand.

Enchant creature
Enchanted creature gets +1/+1 and has flying.
When Skypath Pilgrimage enters, journey twice. (Exile the top two cards of your library face up. Whenever a creature you control deals combat damage to an opponent, put a journeyed card you own into your hand.)

Spark New Life deals X damage to any target. You may put up to X land cards from your hand and/or graveyard onto the battlefield.

When Suburban Runebrawler enters, exile target instant or sorcery card with mana value 2 or less from your graveyard.
Landfall — Once each turn, when a land you control enters, you may cast a copy of the exiled card without paying its mana cost.

When Sunwright Scion enters, put a +1/+1 counter on each other creature you control.
At the beginning of each combat, you may have target creature with a +1/+1 counter on it gain your choice of vigilance, lifelink, or trample until end of turn.

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Create a tapped colorless Mountain Forest land token. (It has “{T}: Add {R} or {G}.”)