msem-instigator

When Kinsang Butcher enters, create a Treasure token.
{1}, Sacrifice an artifact or another creature: Put a +1/+1 counter on Kinsang Butcher. Activate only as a sorcery.

When Kizoku Valiant enters or dies, you gain 2 life.
Art of war — At the beginning of your end step, if Kizoku Valiant dealt damage to an opponent this turn, put a +1/+1 counter on it.

Whenever Knight of the Verdigris deals combat damage to a player, you may sacrifice it. If you do, search your library for a green legendary creature card, reveal it, put it into your hand, then shuffle.

Trample
Leafdown Hunk enters with two +1/+1 counters on it if you control another creature with power 4 or greater.

Heroic — Whenever you cast a spell that targets Leina Tower Sentry, put a +1/+1 counter on Leina Tower Sentry and you gain 1 life.

Reach
{2}{G}, {T}, Sacrifice this creature: It deals 4 damage to target creature with flying.

Reach
Each other creature you control gets +1/+1 for each +1/+1 counter on it.

{2}{G}: Loreweaver's base power and toughness each become equal to the number of cards in your graveyard until end of turn.

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.)
Hexproof

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{1}, {T}: Look at the top card of your library. You may put the card back or into your graveyard.

When Master Chef enters, create a 0/1 green Plant creature token.
Sacrifice a Plant: You gain 3 life.

When Meadow Songstress enters, conjure three cards named Meadow Songstress and shuffle them into your main library.
Whenever a nontoken creature you control enters, if it shares a name with one or more other creatures you control, draw a card.

Whenever another creature with power 4 or greater you control enters, you may draw a card.

Flash
When Mighty Beetle enters, you may put two +1/+1 counters on target creature you control.

Molting Abomination can't be blocked by creatures with power 2 or less.
Whenever Molting Abomination deals combat damage to a player or planeswalker, create a tapped 3/2 colorless Horror creature token. Put a stun counter on that token. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Trample
When Moranai Outriders enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.

Moranai Survivalist enters with three +1/+1 counters on it if you didn't cast it from your hand.
Revive {3}{G}{G} ({3}{G}{G}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Mortal Tapestry gets +1/+1 for each land card in your graveyard.
Revive {4}{G} ({4}{G}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

When Naga Cultivator enters, you may put a land card from your hand onto the battlefield.

When Naiad of the Glen 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.”)
Naiad of the Glen has trample as long as it has a +1/+1 counter on it.

When Neo-Alchemist enters, you may reappropriate. If you do, distribute two +1/+1 counters among creatures you control. Otherwise, put a +1/+1 counter on up to one target creature you control. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

Whenever a land you control enters, put a +1/+1 counter on Nimble Pathfinder.
Surpass {5}{G} ({5}{G}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Whenever you cast a cryptic spell, Oasis Cattle gets +1/+1 until end of turn, then untap it. (Artifacts, enchantments, and modal spells are cryptic.)

Oldgrove Nurturer enters with a +1/+1 counter on it.
{G}, Remove a +1/+1 counter from a creature you control: Create a 1/1 colorless Construct artifact creature token.