Timberwatch Elf

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

Elvish Mystic

Elvish Eulogist

Sacrifice Elvish Eulogist: You gain 1 life for each Elf card in your graveyard.

Weatherseed Elf

{T}: Target creature gains forestwalk until end of turn. (It can't be blocked as long as defending player controls a Forest.)

Arbor Elf

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.

Abomination of Llanowar

Vigilance; menace (This creature can't be blocked except by two or more creatures.)
Abomination of Llanowar's power and toughness are each equal to the number of Elves you control plus the number of Elf cards in your graveyard.

Cruel Feeding

Strive — This spell costs {2}{B} more to cast for each target beyond the first.
Any number of target creatures each get +1/+0 and gain lifelink until end of turn. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Elvish Champion

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

Elvish Pioneer

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

Elvish Promenade

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

Farhaven Elf

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

Elvish Piper

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

Elvish Lyrist

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

Elvish Archdruid

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

Elvish Herder

{G}: Target creature gains trample until end of turn.

Elvish Guidance

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