Wirewood Hivemaster

Whenever another nontoken Elf enters, you may create a 1/1 green Insect creature token.

Wellwisher

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

Tribal Forcemage

Morph {1}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Tribal Forcemage is turned face up, creatures of the creature type of your choice get +2/+2 and gain trample until end of turn.

Timberwatch Elf

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

Pendelhaven Elder

{T}: Each 1/1 creature you control gets +1/+2 until end of turn.

Back to Nature

Elvish Promenade

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

Whip Silk

Enchant creature
Enchanted creature has reach. (It can block creatures with flying.)
{G}: Return Whip Silk to its owner's hand.

Paragon of Eternal Wilds

Other green creatures you control get +1/+1.
{G}, {T}: Another target green creature you control gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Naturalize

Druid's Deliverance

Prevent all combat damage that would be dealt to you this turn. Populate. (Create a token that's a copy of a creature token you control.)

Aspect of Hydra

Target creature gets +X/+X until end of turn, where X is your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Gyre Sage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on Gyre Sage.

Predator's Rapport

Choose target creature you control. You gain life equal to that creature's power plus its toughness.

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Elvish Guidance

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G} for each Elf on the battlefield.

Windstorm

Windstorm deals X damage to each creature with flying.

Taunting Elf

All creatures able to block Taunting Elf do so.

Biorhythm

Each player's life total becomes the number of creatures they control.

Wirewood Channeler

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

Dragon Fangs

Enchant creature
Enchanted creature gets +1/+1 and has trample.
When a creature with mana value 6 or greater enters, you may return Dragon Fangs from your graveyard to the battlefield attached to that creature.

Staff of the Wild Magus

Whenever you cast a green spell or a Forest you control enters, you gain 1 life.

Trollhide

Enchant creature
Enchanted creature gets +2/+2 and has "{1}{G}: Regenerate this creature." (The next time the creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Elvish Branchbender

{T}: Until end of turn, target Forest becomes an X/X Treefolk creature in addition to its other types, where X is the number of Elves you control.

Titanic Growth

Target creature gets +4/+4 until end of turn.

Elven Riders

Elven Riders can't be blocked except by Walls and/or creatures with flying.

Heedless One

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

Forest

Everglove Courier

You may choose not to untap Everglove Courier during your untap step.
{2}{G}, {T}: Target Elf creature gets +2/+2 and has trample for as long as Everglove Courier remains tapped.

Lys Alana Huntmaster

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

Lure

Enchant creature
All creatures able to block enchanted creature do so.

Elvish Vanguard

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

Tribal Unity

Creatures of the creature type of your choice get +X/+X until end of turn.

Arbor Colossus

Reach
{3}{G}{G}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Arbor Colossus becomes monstrous, destroy target creature with flying an opponent controls.