Leyline of Abundance

If Leyline of Abundance is in your opening hand, you may begin the game with it on the battlefield.
Whenever you tap a creature for mana, add an additional {G}.
{6}{G}{G}: Put a +1/+1 counter on each creature you control.

Elvish Vanguard

Whenever another Elf enters, put a +1/+1 counter on Elvish Vanguard.

Have

Joraga Warcaller

Multikicker {1}{G} (You may pay an additional {1}{G} any number of times as you cast this spell.)
Joraga Warcaller enters with a +1/+1 counter on it for each time it was kicked.
Other Elf creatures you control get +1/+1 for each +1/+1 counter on Joraga Warcaller.

Crown of Skemfar

Enchant creature
Enchanted creature gets +1/+1 for each Elf you control and has reach.
{2}{G}: Return Crown of Skemfar from your graveyard to your hand.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Allosaurus Shepherd

This spell can't be countered.
Green spells you control can't be countered.
{4}{G}{G}: Until end of turn, each Elf creature you control has base power and toughness 5/5 and becomes a Dinosaur in addition to its other creature types.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Pennon Blade

Equipped creature gets +1/+1 for each creature you control.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Shamanic Revelation

Draw a card for each creature you control.
Ferocious — You gain 4 life for each creature you control with power 4 or greater.

Wild Onslaught

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Put a +1/+1 counter on each creature you control. If this spell was kicked, put two +1/+1 counters on each creature you control instead.

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.

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.

Nissa Revane

+1: Search your library for a card named Nissa's Chosen, put it onto the battlefield, then shuffle.
+1: You gain 2 life for each Elf you control.
−7: Search your library for any number of Elf creature cards, put them onto the battlefield, then shuffle.

Canopy Tactician

Other Elves you control get +1/+1.
{T}: Add {G}{G}{G}.

Elvish Archdruid

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

Durable Handicraft

Whenever a creature you control enters, you may pay {1}. If you do, put a +1/+1 counter on that creature.
{5}{G}, Sacrifice Durable Handicraft: Put a +1/+1 counter on each creature you control.

Dwynen's Elite

When this creature enters, if you control another Elf, create a 1/1 green Elf Warrior creature token.

Drove of Elves

Hexproof
Drove of Elves's power and toughness are each equal to the number of green permanents you control.

Forest

Greenwood Sentinel

Vigilance (Attacking doesn't cause this creature to tap.)

Decree of Savagery

Put four +1/+1 counters on each creature you control.
Cycling {4}{G}{G} ({4}{G}{G}, Discard this card: Draw a card.)
When you cycle Decree of Savagery, you may put four +1/+1 counters on target creature.

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Immaculate Magistrate

{T}: Put a +1/+1 counter on target creature for each Elf you control.

Elvish Mystic

Llanowar Tribe

Collective Unconscious

Draw a card for each creature you control.

Doubling Chant

For each creature you control, you may search your library for a creature card with the same name as that creature. Put those cards onto the battlefield, then shuffle.

Freyalise, Llanowar's Fury

+2: Create a 1/1 green Elf Druid creature token with "{T}: Add {G}."
−2: Destroy target artifact or enchantment.
−6: Draw a card for each green creature you control.
Freyalise, Llanowar's Fury can be your commander.

Elvish Visionary

When Elvish Visionary enters, draw a card.

Hunting Triad

Create three 1/1 green Elf Warrior creature tokens.
Reinforce 3—{3}{G} ({3}{G}, Discard this card: Put three +1/+1 counters on target creature.)

Bramblewood Paragon

Each other Warrior creature you control enters with an additional +1/+1 counter on it.
Each creature you control with a +1/+1 counter on it has trample.

Dwynen, Gilt-Leaf Daen

Reach (This creature can block creatures with flying.)
Other Elf creatures you control get +1/+1.
Whenever Dwynen attacks, you gain 1 life for each attacking Elf you control.

Lifecrafter's Gift

Put a +1/+1 counter on target creature, then put a +1/+1 counter on each creature you control with a +1/+1 counter on it.

Gaea's Cradle

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

Imperious Perfect

Other Elves you control get +1/+1.
{G}, {T}: Create a 1/1 green Elf Warrior creature token.

Elvish Pathcutter

{2}{G}: Target Elf creature gains forestwalk until end of turn. (It can't be blocked as long as defending player controls a Forest.)

Elvish Promenade

Create a 1/1 green Elf Warrior creature token for each Elf you control.

Eladamri, Lord of Leaves

Other Elf creatures have forestwalk. (They can't be blocked as long as defending player controls a Forest.)
Other Elves have shroud. (They can't be the targets of spells or abilities.)

Lys Alana Huntmaster

Whenever you cast an Elf spell, you may create a 1/1 green Elf Warrior creature token.