msem-instigator

When Sear, Forged of Lava enters, create a 3/3 red Panda creature token, then attach it to that token.
Equipped creature gets +3/+3, has flying, haste, and “Whenever this creature dies, it deals 3 damage to target opponent or planeswalker.”
Equip {2}{R}{R}

When Voliv Ritualist enters, choose two different basic land types. Create a tapped colorless land token that's the chosen types. When Voliv Ritualist is no longer on the battlefield, sacrifice a land.

Trample
Avatar of the Groves enters with a +1/+1 counter on it for each land you control.
Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Adorned — Commoners' Favored gets +2/+2 as long as it's equipped and/or enchanted.

Landfall — Whenever a land you control enters, you may pay {1}{G}. If you do, create a 2/2 green Wolf creature token.

When Elvish Skyranger enters, search your library for a card with a basic land type, put it onto the battlefield tapped, then shuffle.

Whenever Elvish Wayfinder enters or attacks, reveal the top four cards of your library. You may put a land card that doesn't share a name with a land you control into your hand. Put the rest on the bottom of your library in any order.

Reveal the top three cards of your library. Put up to one creature or Revelation card from among them into your hand and the rest into your graveyard.
Coalesce {6}{G} (You may cast this from your graveyard for {6}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Hold Life in Taloned Grasp's power is equal to the number of cards in your graveyard.

Horizon Wayfarer's power and toughness are each equal to the number of differently named lands you control.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
You may play any number of lands on each of your turns.

Ward {2}
Whenever one or more Auras you control enter for the first time each turn, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature.” attached to target creature.)
Keeper of Secret Havens gets +1/+1 for each Aura you control.

Reveal the top five cards of your library. Put a creature or enchantment card from among them into your hand. Put the rest on the bottom of your library in a random order.

Each other creature you control that's an Elf or a Warrior gets +1/+1.
{2}, Sacrifice Llanowar Exemplar: Creatures you control gain indestructible until end of turn.

When Loresprout enters, if you control another creature, draw a card.

Creatures you control get +2/+2.
Wanderlust — As long as you control four or more differently named lands, creatures you control have trample and can't be blocked by more than one creature.

Reach
When Mawdryk's Harrier enters, look at the top six cards of your library. You may put an Elf card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Other Elves you control get +1/+1.

Other creatures you control get +2/+2.

Target creature you control gains indestructible until end of turn if it has a +1/+1 counter on it. Then it fights target creature you don't control.

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.)

At the beginning of your upkeep, mill two cards.

Ravenous Hydra enters with X +1/+1 counters on it.
Whenever Ravenous Hydra deals combat damage, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)

Whenever you create one or more non-Mutant creature tokens, choose one —
• Create a 0/0 green Plant Mutant creature token, then put a +1/+1 counter on it for each of those non-Mutant tokens.
• Draw a card.

Search your library for two basic land cards and put them onto the battlefield tapped. Then they become 0/1 green Plant creatures with “This creature can't block” in addition to their other colors, types, and abilities.

Deathtouch
When The Terror of Shady Cove enters, target opponent sacrifices an artifact. If they can't, create a 3/3 green Slug creature token with deathtouch. Then repeat this process for an enchantment and a nonbasic land.

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.)