msem-instigator

Hexproof
Whenever one or more cards are put into your graveyard from anywhere, Creeping Hidebehind gets +1/+0 until end of turn.

{2}{G}: Cryptozoologist voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Cryptozoologist phases in, you may put a creature card from your hand onto the battlefield until Cryptozoologist leaves the battlefield. (It returns to your hand if it's still on the battlefield.)

Tap two untapped Elves you control: Add {G}{G}.
{6}{G}{G}: Create an 8/8 green Elemental creature token.

Haste
When Dedicated Bushwacker enters, other creatures you control get +1/+0 and gain haste until end of turn.

Flash
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Trample
At the beginning of your upkeep, sacrifice another creature. If you do, put X +1/+1 counters on Demented Host, where X is that creature's power.

When Detritus Scourge enters, you mill eight cards. Put a +1/+1 counter on Detritus Scourge for each creature card milled this way.

Defender
Whenever another player casts an instant or sorcery spell, Devouring Spellroot gets +2/+2 until end of turn.

When Diasune Irregular enters, if you control another Warrior, draw a card.

Whenever you cast a blue spell, you may cast creature spells this turn as though they had flash.
Whenever you cast a black spell, put up to one target card from your graveyard on top of your library.

Each other nontoken Elf and/or Warrior you control enters with an additional +1/+1 counter on it.
{G}{G}, {T}, Remove two +1/+1 counters from among creatures you control: Create two 1/1 green Elf Warrior creature tokens.

{4}{G}{G}: Eager Voyager voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Eager Voyager phases in, if it has no +1/+1 counters on it, put four +1/+1 counters on it.

{4}{G}, Sacrifice Elvish Godtracker: Create a 5/5 green Beast 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.

When Evanescier Greypelt enters, it fights target creature.
Mirage {3}{G} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Other Elves you control get +1/+1.
Whenever another Scout you control deals combat damage to a player, you may reveal the top card of your library. If it's a land card, put it onto the battlefield tapped.

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
Vigilance, haste
{T}: Add {G}. If a creature died under your control this turn, add {G}{G} instead.

At the beginning of your end step, if a counter was put on a permanent you control or controlled this turn, draw a card.

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.)
This creature gets +2/+2 as long as it's merged with another card or token.

When Feralborn Druid enters, create two 2/2 green Wolf creature tokens.
Feralborn Druid gets +1/+1 for each Wolf you control.

Deathtouch
When Flesheater Vine enters, you may have it consume. If you do, put a +1/+1 counter on it and you gain 3 life. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

Whenever an Aura you control enters, draw a card.

Noncreature spells you cast cost {1} more to cast.
Noncreature spells your opponents cast cost {1} more to cast unless that player controls more creatures than you.

Bulwark — At the beginning of each upkeep, if you control a creature with toughness 4 or greater, Fortress Sentinel gains hexproof until end of turn.

Friend of the Woods has hexproof as long as it has a +1/+1 counter on it.
{1}{G}, {T}: Put a +1/+1 counter on Friend of the Woods.