Wirewood Pride

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

Elvish Promenade

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

Timberwatch Elf

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

Talara's Battalion

Cast this spell only if you've cast another green spell this turn.
Trample

Imperious Perfect

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

Wellwisher

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

Elvish Archdruid

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

Wirewood Channeler

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

Echoing Courage

Target creature and all other creatures with the same name as that creature get +2/+2 until end of turn.

Immaculate Magistrate

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

Forest

Elvish Champion

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

Presence of Gond

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

Elvish Harbinger

When this creature 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.

Llanowar Sentinel

When this creature enters, you may pay {1}{G}. If you do, search your library for a card named Llanowar Sentinel, put that card onto the battlefield, then shuffle.

Wurm's Tooth

Whenever a player casts a green spell, you may gain 1 life.

Heedless One

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

Sylvan Messenger

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When this creature enters, reveal the top four cards of your library. Put all Elf cards revealed this way into your hand and the rest on the bottom of your library in any order.