Unclaimed Territory

As Unclaimed Territory enters the battlefield, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Arbor Elf

Gilt-Leaf Palace

As Gilt-Leaf Palace enters the battlefield, you may reveal an Elf card from your hand. If you don't, Gilt-Leaf Palace enters the battlefield tapped.
{T}: Add {B} or {G}.

Llanowar Elves

Elvish Champion

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

Thornbow Archer

Whenever Thornbow Archer attacks, each opponent who doesn't control an Elf loses 1 life.

Ezuri, Renegade Leader

{G}: Regenerate another target Elf.
{2}{G}{G}{G}: Elf creatures you control get +3/+3 and gain trample until end of turn.

Dwynen's Elite

When Dwynen's Elite enters the battlefield, if you control another Elf, create a 1/1 green Elf Warrior creature token.

Forest

Reclamation Sage

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

Elvish Archdruid

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

Shaman of the Pack

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

Elvish Warmaster

Whenever one or more other Elves enter the battlefield under your control, 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.