Priest of Titania

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

Adeline, Resplendent Cathar

Vigilance
Adeline, Resplendent Cathar's power is equal to the number of creatures you control.
Whenever you attack, for each opponent, create a 1/1 white Human creature token that's tapped and attacking that player or a planeswalker they control.

Forest

Essence Warden

Whenever another creature enters, you gain 1 life.

Presence of Gond

Enchant creature
Enchanted creature has "{T}: Create a 1/1 green Elf Warrior creature token."

Soul Warden

Plains

Midnight Guard

Whenever another creature enters, untap Midnight Guard.

Mirror Gallery

Wurm's Tooth

Whenever a player casts a green spell, you may gain 1 life.

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Wellwisher

{T}: You gain 1 life for each Elf on the battlefield.

Elvish Archdruid

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