msem-instigator

Elemental Envelopment enters with X +1/+1 counters on it.
When Elemental Envelopment enters, if you controlled a green legendary creature or planeswalker as you cast it, search your library for any number of Elemental creature cards with total mana value X or less, where X is Elemental Envelopment's power, put them onto the battlefield, then shuffle.

Target creature gets +X/+X until end of turn, where X is 3 plus the number of cards named Elemental Power in your graveyard.

Choose one —
• Target creature you control deals damage equal to its power to another target creature or planeswalker.
• Target planeswalker you control deals damage equal to the number of loyalty counters on it to target creature or planeswalker.

Elrayin, the Manaroot enters tapped.
Whenever you tap another land for mana, put a creation counter on Elrayin.
{T}, Remove ten creation counters from Elrayin and sacrifice it: Untap all lands target player controls.

Hexproof, reach

When Elven Guard becomes the target of a spell you control, you may pay {G}. If you do, transform it.

(Transform this if it's not attached to a creature. Pay {3}{G} as a sorcery to unattach it.)
Enchant creature you control
Elven Mount's rider gets +3/+3 and has trample.

At the beginning of combat on your turn, look at the top card of your library. You may reveal it. If you do, target creature gets +X/+X until end of turn, where X is the revealed card's mana value.

{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.

Elfcycling {2}{G} ({2}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, 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.

Scry 2. (Then exile this card. You may cast the creature later from exile.)

When Embodiment of Abundance enters, choose one —
• Search your library for up to X basic land cards, where X is the number of lands you control, and put them onto the battlefield tapped. Then shuffle.
• Create a 1/1 green Elf Druid creature token for each creature you control.

Trample
Other Elementals you control get +1/+0 and have trample.

At the beginning of combat on your turn, choose one —
• Embodiment of Nature gains haste and hexproof until your next turn.
• Embodiment of Nature gains vigilance and indestructible until your next turn.
• Embodiment of Nature gets +2/+2 and gains trample until your next turn.

Choose one —
• Create two 1/1 blue Tentacle creature tokens.
• Untap target creature. It gets +2/+4 until end of turn.

Emissary of Dai Gui enters tapped.
Emissary of Dai Gui doesn't untap during your untap step unless it's in a pack. (Two or more creatures you control with equal power are in a pack.)
Creature spells you cast cost {1} less to cast.

Vigilance
Art of war — At the beginning of your end step, if Emperor Kenshiro dealt damage to an opponent this turn, you may put a creature card from your hand onto the battlefield tapped.

Target creature you control gets +X/+X until end of turn, where X is the number of +1/+1 counters among creatures you control.

Whenever Encouraging Bulwark attacks, you may put a +1/+1 counter on each creature you control that's enchanted and/or has one or more counters on it.

Trample
When Endangered Rhino dies, 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.”)

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.

Colossal 4—{4}{G}{G}{G} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {4}{G}{G}{G} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever a nontoken creature you control with a counter on it dies, create a 4/4 green Hydra creature token.