Elvish Archdruid

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

Gnarlroot Trapper

{T}, Pay 1 life: Add {G}. Spend this mana only to cast an Elf creature spell.
{T}: Target attacking Elf you control gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Galadriel, Elven-Queen

Will of the council — At the beginning of combat on your turn, if another Elf entered the battlefield under your control this turn, starting with you, each player votes for dominion or guidance. If dominion gets more votes, the Ring tempts you, then you put a +1/+1 counter on your Ring-bearer. If guidance gets more votes or the vote is tied, draw a card.

Elvish Promenade

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

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.

Doors of Durin

Whenever you attack, scry 2, then you may reveal the top card of your library. If it's a creature card, put it onto the battlefield tapped and attacking. Until your next turn, it gains trample if you control a Dwarf and hexproof if you control an Elf.

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.

Rukarumel, Biologist

As Rukarumel, Biologist enters, choose a creature type.
Slivers you control and nontoken creatures you control are the chosen type in addition to their other creature types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 1/1 colorless Sliver creature token.

Elvish Vanguard

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

Elderfang Venom

Attacking Elves you control have deathtouch.
Whenever an Elf you control dies, each opponent loses 1 life and you gain 1 life.

Elven Ambush

Elvish Guidance

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

Dwynen, Gilt-Leaf Daen

Reach
Other Elf creatures you control get +1/+1.
Whenever Dwynen, Gilt-Leaf Daen attacks, you gain 1 life for each attacking Elf you control.

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.