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.

Fyndhorn Elves

Priest of Titania

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

Raggadragga, Goreguts Boss

Each creature you control with a mana ability gets +2/+2.
Whenever a creature you control with a mana ability attacks, untap it.
Whenever you cast a spell, if at least seven mana was spent to cast it, untap target creature. It gets +7/+7 and gains trample until end of turn.

Viridian Joiner

{T}: Add an amount of {G} equal to Viridian Joiner's power.

Regal Force

When Regal Force enters, draw a card for each green creature you control.

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.

Radha, Heir to Keld

Whenever Radha, Heir to Keld attacks, you may add {R}{R}.
{T}: Add {G}.

Elvish Archdruid

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

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)