Full Flowering

Populate X times. (To populate, create a token that's a copy of a creature token you control. Do this X times.)

Have

Wirewood Pride

Target creature gets +X/+X until end of turn, where X is the number of Elves on the battlefield.

Ambush Commander

Forests you control are 1/1 green Elf creatures that are still lands.
{1}{G}, Sacrifice an Elf: Target creature gets +3/+3 until end of turn.

Getting

Primal Vigor

If one or more tokens would be created, twice that many of those tokens are created instead.
If one or more +1/+1 counters would be put on a creature, twice that many +1/+1 counters are put on that creature instead.

Ambassador Oak

When Ambassador Oak enters, create a 1/1 green Elf Warrior creature token.

Dwynen's Elite

When this creature enters, if you control another Elf, create a 1/1 green Elf Warrior creature token.

Wellwisher

{T}: You gain 1 life for each Elf on the battlefield.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Voice of the Woods

Tap five untapped Elves you control: Create a 7/7 green Elemental creature token with trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Elvish Archdruid

Other Elf creatures you control get +1/+1.
{T}: Add {G} for each Elf you control.

Elvish Harbinger

When Elvish Harbinger enters, you may search your library for an Elf card, reveal it, then shuffle and put that card on top.
{T}: Add one mana of any color.

Allosaurus Shepherd

This spell can't be countered.
Green spells you control can't be countered.
{4}{G}{G}: Until end of turn, each Elf creature you control has base power and toughness 5/5 and becomes a Dinosaur in addition to its other creature types.

Elvish Clancaller

Other Elves you control get +1/+1.
{4}{G}{G}, {T}: Search your library for a card named Elvish Clancaller, put it onto the battlefield, then shuffle.

Elfsworn Giant

Reach (This creature can block creatures with flying.)
Landfall — Whenever a land you control enters, create a 1/1 green Elf Warrior creature token.

Wirewood Lodge

{T}: Add {C}.
{G}, {T}: Untap target Elf.

Windswift Slice

Target creature you control deals damage equal to its power to target creature you don't control. Create a number of 1/1 green Elf Warrior creature tokens equal to the amount of excess damage dealt this way.

Quirion Elves

As Quirion Elves enters, choose a color.
{T}: Add {G}.
{T}: Add one mana of the chosen color.

Kaysa

Wirewood Herald

When Wirewood Herald dies, you may search your library for an Elf card, reveal that card, put it into your hand, then shuffle.

Elvish Warmaster

Whenever one or more other Elves you control enter, create a 1/1 green Elf Warrior creature token. This ability triggers only once each turn.
{5}{G}{G}: Elves you control get +2/+2 and gain deathtouch until end of turn.

Priest of Titania

{T}: Add {G} for each Elf on the battlefield.

Llanowar Visionary

When Llanowar Visionary enters, draw a card.
{T}: Add {G}.

Mirkwood Channeler

At the beginning of combat on your turn, target Elf you control gains trample and gets +X/+X until end of turn, where X is the number of Forests you control.

Elvish Promenade

Create a 1/1 green Elf Warrior creature token for each Elf you control.

Llanowar Tribe

Gilt-Leaf Ambush

Create two 1/1 green Elf Warrior creature tokens. Clash with an opponent. If you win, those creatures gain deathtouch until end of turn. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value. Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Haldir, Lórien Lieutenant

Haldir, Lórien Lieutenant enters with X +1/+1 counters on it.
Vigilance
{5}{G}: Until end of turn, other Elves you control gain vigilance and get +1/+1 for each +1/+1 counter on Haldir.

Fyndhorn Elder

Hunting Triad

Create three 1/1 green Elf Warrior creature tokens.
Reinforce 3—{3}{G} ({3}{G}, Discard this card: Put three +1/+1 counters on target creature.)

Ezuri, Renegade Leader

{G}: Regenerate another target Elf.
{2}{G}{G}{G}: Elf creatures you control get +3/+3 and gain trample until end of turn.

Sylvan Offering

Choose an opponent. You and that player each create an X/X green Treefolk creature token.
Choose an opponent. You and that player each create X 1/1 green Elf Warrior creature tokens.

Timberwatch Elf

{T}: Target creature gets +X/+X until end of turn, where X is the number of Elves on the battlefield.

Eladamri, Korvecdal

You may look at the top card of your library any time.
You may cast creature spells from the top of your library.
{G}, {T}, Tap two untapped creatures you control: Reveal a card from your hand or the top card of your library. If you reveal a creature card this way, put it onto the battlefield. Activate only during your turn.

Dwynen, Gilt-Leaf Daen

Reach (This creature can block creatures with flying.)
Other Elf creatures you control get +1/+1.
Whenever Dwynen attacks, you gain 1 life for each attacking Elf you control.

Marwyn, the Nurturer

Whenever another Elf you control enters, put a +1/+1 counter on Marwyn, the Nurturer.
{T}: Add an amount of {G} equal to Marwyn's power.

Elderleaf Mentor

When Elderleaf Mentor enters, create a 1/1 green Elf Warrior creature token.

Wolverine Riders

At the beginning of each upkeep, create a 1/1 green Elf Warrior creature token.
Whenever another Elf you control enters, you gain life equal to its toughness.

Farhaven Elf

When Farhaven Elf enters, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Joraga Warcaller

Multikicker {1}{G} (You may pay an additional {1}{G} any number of times as you cast this spell.)
Joraga Warcaller enters with a +1/+1 counter on it for each time it was kicked.
Other Elf creatures you control get +1/+1 for each +1/+1 counter on Joraga Warcaller.

Elven Ambush

Forest

Sol Ring

Arboreal Alliance

When Arboreal Alliance enters, create an X/X green Treefolk creature token.
Whenever you attack with one or more Elves, populate. (Create a token that's a copy of a creature token you control.)

Parallel Evolution

For each creature token on the battlefield, its controller creates a token that's a copy of that creature.
Flashback {4}{G}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Circle of Dreams Druid

{T}: Add {G} for each creature you control.

Llanowar Elves

Immaculate Magistrate

{T}: Put a +1/+1 counter on target creature for each Elf you control.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Heedless One

Trample
Heedless One's power and toughness are each equal to the number of Elves on the battlefield.

Drove of Elves

Hexproof
Drove of Elves's power and toughness are each equal to the number of green permanents you control.

Eladamri, Lord of Leaves

Other Elf creatures have forestwalk. (They can't be blocked as long as defending player controls a Forest.)
Other Elves have shroud. (They can't be the targets of spells or abilities.)

Sharpshooter Elf

Reach
Sharpshooter Elf's power is equal to the number of creatures you control.
When Sharpshooter Elf enters, it deals damage equal to its power to target creature with flying an opponent controls.

Quirion Ranger

Return a Forest you control to its owner's hand: Untap target creature. Activate only once each turn.

Elvish Champion

Other Elf creatures get +1/+1 and have forestwalk. (They can't be blocked as long as defending player controls a Forest.)

Mosswort Bridge

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Mosswort Bridge enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Wirewood Channeler

{T}: Add X mana of any one color, where X is the number of Elves on the battlefield.

Canopy Tactician

Other Elves you control get +1/+1.
{T}: Add {G}{G}{G}.

Imaryll, Elfhame Elite

Whenever Imaryll, Elfhame Elite attacks, it gets +X/+X until end of turn, where X is the number of other Elves you control.
You may have Imaryll assign its combat damage as though it weren't blocked.

Galadhrim Brigade

Squad {1}{G} (As an additional cost to cast this spell, you may pay {1}{G} any number of times. When this creature enters, create that many tokens that are copies of it.)
Other Elves you control get +1/+1.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Elvish Piper

{G}, {T}: You may put a creature card from your hand onto the battlefield.

Fyndhorn Elves

Galadhrim Ambush

Create X 1/1 green Elf Warrior creature tokens, where X is the number of attacking creatures.
Prevent all combat damage that would be dealt this turn by non-Elf creatures.

Flourishing Defenses

Whenever a -1/-1 counter is put on a creature, you may create a 1/1 green Elf Warrior creature token.

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Second Harvest

For each token you control, create a token that's a copy of that permanent.

Bounty of Skemfar

Reveal the top six cards of your library. You may put up to one land card from among them onto the battlefield tapped and up to one Elf card from among them into your hand. Put the rest on the bottom of your library in a random order.

Leaf-Crowned Visionary

Other Elves you control get +1/+1.
Whenever you cast an Elf spell, you may pay {G}. If you do, draw a card.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Elvish Mystic

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Imperious Perfect

Other Elves you control get +1/+1.
{G}, {T}: Create a 1/1 green Elf Warrior creature token.

Lys Alana Huntmaster

Whenever you cast an Elf spell, you may create a 1/1 green Elf Warrior creature token.

Taunting Elf

All creatures able to block Taunting Elf do so.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Crown of Skemfar

Enchant creature
Enchanted creature gets +1/+1 for each Elf you control and has reach.
{2}{G}: Return Crown of Skemfar from your graveyard to your hand.

Presence of Gond

Enchant creature
Enchanted creature has "{T}: Create a 1/1 green Elf Warrior creature token."

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Elvish Vanguard

Whenever another Elf enters, put a +1/+1 counter on Elvish Vanguard.