Cavern of Souls

As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {1} to your mana pool. {T}: Add one mana of any color to your mana pool. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Nettle Sentinel

Nettle Sentinel doesn't untap during your untap step. Whenever you play a green spell, you may untap Nettle Sentinel.

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G} to your mana pool.") Dryad Arbor is green.

Fyndhorn Elves

{T}: Add {G} to your mana pool. Play this ability as an interrupt.

Reclamation Sage

When Reclamation Sage enters the battlefield, you may destroy target artifact or enchantment.

Sylvan Messenger

Trample (This creature can deal excess combat damage to defending player or planeswalker while attacking.) When Sylvan Messenger enters the battlefield, reveal the top four cards of your library. Put all Elf cards revealed this way into your hand and the rest on the bottom of your library in any order.

Green Sun's Zenith

Search your library for a green creature card with converted mana cost X or less, put it onto the battlefield, then shuffle your library. Shuffle Green Sun's Zenith into its owner's library.

Mirror Entity

Changeling (This card is every creature type at all times.) {X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Heritage Druid

Tap three untapped Elves you control: Add {G}{G}{G} to your mana pool.

Birchlore Rangers

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

Elvish Mystic

{T}: Add {G} to your mana pool.

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.

Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Play this ability only once each turn.

Savannah

Counts as both plains and forest and is affected by spells that affect either. Tap to add either {W} or {G} to your mana pool.

Llanowar Elves

Tap to add green mana to your mana pool. This tap can be played as an interrupt.

Crop Rotation

At the time you play Crop Rotation, sacrifice a land. Search your library for a land card and put that land into play. Shuffle your library afterwards.

Priest of Titania

{T}: Add {G} to your mana pool for each Elf in play. Play this ability as a mana source.

Gaea's Cradle

{T}: Add {G} to your mana pool for each creature you control.

Quirion Ranger

Return a forest you control to owner's hand: Untap target creature. Use this ability only once each turn.

Misty Rainforest

Verdant Catacombs

Windswept Heath

Wooded Foothills

Elvish Visionary

Horizon Canopy

Wasteland

Forest

({T}: Add {G}.)