Glissa Sunseeker

First strike
{T}: Destroy target artifact if its mana value is equal to the amount of unspent mana you have.

Essence Warden

Whenever another creature enters, you gain 1 life.

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.

Rishkar, Peema Renegade

When Rishkar, Peema Renegade enters, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

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.

Imaryll, Elfhame Elite

Whenever Imaryll, Elfhame Elite attacks, it gets +X/+X until end of turn, where X is the number of other Elves you control.
You may have Imaryll assign its combat damage as though it weren't blocked.

Elvish Clancaller

Other Elves you control get +1/+1.
{4}{G}{G}, {T}: Search your library for a card named Elvish Clancaller, put it onto the battlefield, then shuffle.

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.

Elvish Champion

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

Haldir, Lórien Lieutenant

Haldir, Lórien Lieutenant enters with X +1/+1 counters on it.
Vigilance
{5}{G}: Until end of turn, other Elves you control gain vigilance and get +1/+1 for each +1/+1 counter on Haldir.

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.