Elvish Archdruid

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

Priest of Titania

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

Ghalta, Primal Hunger

This spell costs {X} less to cast, where X is the total power of creatures you control.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Forest

Fyndhorn Elves

Llanowar Elves

Birchlore Rangers

Tap two untapped Elves you control: Add one mana of any color.
Morph {G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Elvish Mystic

Blanchwood Armor

Enchant creature
Enchanted creature gets +1/+1 for each Forest you control.

Heritage Druid

Tap three untapped Elves you control: Add {G}{G}{G}.

Llanowar Tribe

Circle of Dreams Druid

{T}: Add {G} for each creature you control.