Shalai and Hallar

Flying, vigilance
Whenever one or more +1/+1 counters are put on a creature you control, Shalai and Hallar deals that much damage to target opponent.

Marwyn, the Nurturer

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

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.

Tolsimir, Midnight's Light

Lifelink
When Tolsimir, Midnight's Light enters the battlefield, create Voja Fenstalker, a legendary 5/5 green and white Wolf creature token with trample.
Whenever a Wolf you control attacks, if Tolsimir attacked this combat, target creature an opponent controls blocks that Wolf this combat if able.

Elvish Archdruid

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

Voja, Jaws of the Conclave

Vigilance, trample, ward {3}
Whenever Voja, Jaws of the Conclave attacks, put X +1/+1 counters on each creature you control, where X is the number of Elves you control. Draw a card for each Wolf you control.