Rhys the Exiled

Whenever Rhys the Exiled attacks, you gain 1 life for each Elf you control.
{B}, Sacrifice an Elf: Regenerate Rhys the Exiled.

Elderfang Venom

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

Fury Sliver

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.

Lathril, Blade of the Elves

Menace
Whenever Lathril, Blade of the Elves deals combat damage to a player, create that many 1/1 green Elf Warrior creature tokens.
{T}, Tap ten untapped Elves you control: Each opponent loses 10 life and you gain 10 life.

Priest of Titania

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

Sinew Sliver

Edric, Spymaster of Trest

Whenever a creature deals combat damage to one of your opponents, its controller may draw a card.

Fungus Sliver

All Sliver creatures have "Whenever this creature is dealt damage, put a +1/+1 counter on it." (It must survive the damage to get the counter.)

Shaman of the Pack

When Shaman of the Pack enters, target opponent loses life equal to the number of Elves you control.

Shadow Sliver

All Sliver creatures have shadow. (They can block or be blocked by only creatures with shadow.)

Blur Sliver

Sliver creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

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.

Imperious Perfect

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

Crypt Sliver

All Slivers have "{T}: Regenerate target Sliver."

Synapse Sliver

Whenever a Sliver deals combat damage to a player, its controller may draw a card.

Crystalline Sliver

All Slivers have shroud. (They can't be the targets of spells or abilities.)

Bonescythe Sliver

Sliver creatures you control have double strike. (They deal both first-strike and regular combat damage.)

Lys Alana Huntmaster

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

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Lancer Sliver

Sliver creatures you control have first strike.

Wirewood Channeler

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

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Constricting Sliver

Sliver creatures you control have "When this creature enters, you may exile target creature an opponent controls until this creature leaves the battlefield."

Elvish Promenade

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

Two-Headed Sliver

All Sliver creatures have menace. (They can't be blocked except by two or more creatures.)

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Shifting Sliver

Slivers can't be blocked except by Slivers.

Venom Sliver

Sliver creatures you control have deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Brood Sliver

Whenever a Sliver deals combat damage to a player, its controller may create a 1/1 colorless Sliver creature token.

Immaculate Magistrate

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

Elvish Archdruid

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

Scuttling Sliver

Sliver creatures you control have "{2}: Untap this creature."

Marwyn, the Nurturer

Whenever another Elf you control enters, put a +1/+1 counter on Marwyn, the Nurturer.
{T}: Add an amount of {G} equal to Marwyn's power.