Priest of Titania

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

Reclamation Sage

When Reclamation Sage enters, you may destroy target artifact or enchantment.

Elvish Champion

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

Birchlore Rangers

Tap two untapped Elves you control: Add one mana of any color.
Morph {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.)

Skyshroud Ranger

{T}: You may put a land card from your hand onto the battlefield. Activate only as a sorcery.

Elvish Vanguard

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

Elvish Pioneer

When Elvish Pioneer enters, you may put a basic land card from your hand onto the battlefield tapped.

Fyndhorn Elder

Heedless One

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

Elvish Guidance

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

Defiant Elf

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Yavimaya Granger

Echo {2}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Yavimaya Granger enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Rampant Growth

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

Fierce Empath

When Fierce Empath enters, you may search your library for a creature card with mana value 6 or greater, reveal it, put it into your hand, then shuffle.

Llanowar Tribe

Wirewood Channeler

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

Reclaim

Put target card from your graveyard on top of your library.

Titania's Chosen

Whenever a player casts a green spell, put a +1/+1 counter on Titania's Chosen.

Hall of Gemstone

At the beginning of each player's upkeep, that player chooses a color. Until end of turn, lands tapped for mana produce mana of the chosen color instead of any other color.

Elvish Lyrist

{G}, {T}, Sacrifice Elvish Lyrist: Destroy target enchantment.

Kaysa

Eladamri's Vineyard

At the beginning of each player's first main phase, that player adds {G}{G}.

Wirewood Elf

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Gempalm Strider

Cycling {2}{G}{G} ({2}{G}{G}, Discard this card: Draw a card.)
When you cycle Gempalm Strider, Elf creatures get +2/+2 until end of turn.

Exploration

You may play an additional land on each of your turns.

Quirion Ranger

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

Abundance

If you would draw a card, you may instead choose land or nonland and reveal cards from the top of your library until you reveal a card of the chosen kind. Put that card into your hand and put all other cards revealed this way on the bottom of your library in any order.

Elvish Mystic

Gaea's Herald

Argothian Elder

Elvish Piper

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

Llanowar Druid

{T}, Sacrifice Llanowar Druid: Untap all Forests.

Llanowar Elves

Defense of the Heart

At the beginning of your upkeep, if an opponent controls three or more creatures, sacrifice Defense of the Heart, search your library for up to two creature cards, put those cards onto the battlefield, then shuffle.

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.)

Elvish Scrapper

{G}, {T}, Sacrifice Elvish Scrapper: Destroy target artifact.

Quirion Trailblazer

When Quirion Trailblazer enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.

Fyndhorn Elves

Norwood Priestess

{T}: You may put a green creature card from your hand onto the battlefield. Activate only during your turn, before attackers are declared.