Urborg, Tomb of Yawgmoth

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

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

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.

Elvish Guidance

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G} for each Elf on the battlefield.

Secluded Courtyard

As Secluded Courtyard enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Reclamation Sage

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

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Shadowheart, Dark Justiciar

{1}{B}, {T}, Sacrifice another creature: Draw X cards, where X is that creature's power.
Choose a Background (You can have a Background as a second commander.)

End-Raze Forerunners

Vigilance, trample, haste
When End-Raze Forerunners enters, other creatures you control get +2/+2 and gain vigilance and trample until end of turn.

Wellwisher

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

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.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Dwynen, Gilt-Leaf Daen

Reach
Other Elf creatures you control get +1/+1.
Whenever Dwynen, Gilt-Leaf Daen attacks, you gain 1 life for each attacking Elf you control.

Mutavault

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Gnarlroot Trapper

{T}, Pay 1 life: Add {G}. Spend this mana only to cast an Elf creature spell.
{T}: Target attacking Elf you control gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Imperious Perfect

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

Leaf-Crowned Visionary

Other Elves you control get +1/+1.
Whenever you cast an Elf spell, you may pay {G}. If you do, draw a card.

Yavimaya, Cradle of Growth

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

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Saryth, the Viper's Fang

Other tapped creatures you control have deathtouch.
Other untapped creatures you control have hexproof.
{1}, {T}: Untap another target creature or land you control.

Command Tower

Elderfang Venom

Attacking Elves you control have deathtouch.
Whenever an Elf you control dies, each opponent loses 1 life and you gain 1 life.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Concordant Crossroads

Return Upon the Tide

Return target creature card from your graveyard to the battlefield. If it's an Elf, create two 1/1 green Elf Warrior creature tokens.
Foretell {3}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Necroblossom Snarl

As Necroblossom Snarl enters, you may reveal a Swamp or Forest card from your hand. If you don't, Necroblossom Snarl enters tapped.
{T}: Add {B} or {G}.

Golgari Findbroker

When Golgari Findbroker enters, return target permanent card from your graveyard to your hand.

Poison-Tip Archer

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another creature dies, each opponent loses 1 life.

Gilt-Leaf Palace

As Gilt-Leaf Palace enters, you may reveal an Elf card from your hand. If you don't, Gilt-Leaf Palace enters tapped.
{T}: Add {B} or {G}.

Ruthless Winnower

At the beginning of each player's upkeep, that player sacrifices a non-Elf creature.

Skemfar Shadowsage

When Skemfar Shadowsage enters, choose one —
• Each opponent loses X life, where X is the greatest number of creatures you control that have a creature type in common.
• You gain X life, where X is the greatest number of creatures you control that have a creature type in common.

Sol Ring

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

Forest

Elvish Archdruid

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Nullmage Shepherd

Tap four untapped creatures you control: Destroy target artifact or enchantment.

Swamp

Rhys the Exiled

Whenever Rhys the Exiled attacks, you gain 1 life for each Elf you control.
{B}, Sacrifice an Elf: Regenerate Rhys the Exiled.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Casualties of War

Choose one or more —
• Destroy target artifact.
• Destroy target creature.
• Destroy target enchantment.
• Destroy target land.
• Destroy target planeswalker.

Circle of Dreams Druid

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

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Abomination of Llanowar

Vigilance; menace (This creature can't be blocked except by two or more creatures.)
Abomination of Llanowar's power and toughness are each equal to the number of Elves you control plus the number of Elf cards in your graveyard.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Canopy Tactician

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

Prowess of the Fair

Whenever another nontoken Elf is put into your graveyard from the battlefield, you may create a 1/1 green Elf Warrior creature token.

Elvish Mystic

Itlimoc, Cradle of the Sun

(Transforms from Growing Rites of Itlimoc.)
{T}: Add {G}.
{T}: Add {G} for each creature you control.

Growing Rites of Itlimoc

When Growing Rites of Itlimoc enters, look at the top four cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
At the beginning of your end step, if you control four or more creatures, transform Growing Rites of Itlimoc.

Growing Rites of Itlimoc // Itlimoc, Cradle of the Sun

Harald, King of Skemfar

Menace (This creature can't be blocked except by two or more creatures.)
When Harald, King of Skemfar enters, look at the top five cards of your library. You may reveal an Elf, Warrior, or Tyvar card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Jagged-Scar Archers

Jagged-Scar Archers's power and toughness are each equal to the number of Elves you control.
{T}: Jagged-Scar Archers deals damage equal to its power to target creature with flying.

Elven Chorus

You may look at the top card of your library any time.
You may cast creature spells from the top of your library.
Creatures you control have "{T}: Add one mana of any color."

Immaculate Magistrate

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

Elvish Warmaster

Whenever one or more other Elves you control enter, create a 1/1 green Elf Warrior creature token. This ability triggers only once each turn.
{5}{G}{G}: Elves you control get +2/+2 and gain deathtouch until end of turn.

Dig Up

Cleave {1}{B}{B}{G} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Search your library for a [basic land] card, [reveal it,] put it into your hand, then shuffle.

Wolverine Riders

At the beginning of each upkeep, create a 1/1 green Elf Warrior creature token.
Whenever another Elf you control enters, you gain life equal to its toughness.

Pact of the Serpent

Choose a creature type. Target player draws X cards and loses X life, where X is the number of creatures they control of the chosen type.

Golgari Rot Farm

Golgari Rot Farm enters tapped.
When Golgari Rot Farm enters, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Cavern of Souls

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

Elvish Champion

Other Elf creatures get +1/+1 and have forestwalk. (They can't be blocked as long as defending player controls a Forest.)

Bounty of Skemfar

Reveal the top six cards of your library. You may put a land card from among them onto the battlefield tapped and an Elf card from among them into your hand. Put the rest on the bottom of your library in a random order.

Harald Unites the Elves

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Mill three cards. You may put an Elf or Tyvar card from your graveyard onto the battlefield.
II — Put a +1/+1 counter on each Elf you control.
III — Whenever an Elf you control attacks this turn, target creature an opponent controls gets -1/-1 until end of turn.

Throne of the God-Pharaoh

At the beginning of your end step, each opponent loses life equal to the number of tapped creatures you control.

Llanowar Elves

Tyvar Kell

Elves you control have "{T}: Add {B}."
+1: Put a +1/+1 counter on up to one target Elf. Untap it. It gains deathtouch until end of turn.
0: Create a 1/1 green Elf Warrior creature token.
−6: You get an emblem with "Whenever you cast an Elf spell, it gains haste until end of turn and you draw two cards."

Binding the Old Gods

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target nonland permanent an opponent controls.
II — Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
III — Creatures you control gain deathtouch until end of turn.

Shaman of the Pack

When Shaman of the Pack enters, target opponent loses life equal to the number of Elves you control.

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.

Wirewood Channeler

{T}: Add X mana of any one color, where X is the number of Elves on the battlefield.

Cryptolith Rite

Creatures you control have "{T}: Add one mana of any color."

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Sylvan Anthem

Green creatures you control get +1/+1.
Whenever a green creature you control enters, scry 1.

Fynn, the Fangbearer

Deathtouch
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Lathril, Blade of the Elves

Menace
Whenever Lathril, Blade of the Elves deals combat damage to a player, create that many 1/1 green Elf Warrior creature tokens.
{T}, Tap ten untapped Elves you control: Each opponent loses 10 life and you gain 10 life.

Harvest Season

Search your library for up to X basic land cards, where X is the number of tapped creatures you control, put those cards onto the battlefield tapped, then shuffle.

Timberwatch Elf

{T}: Target creature gets +X/+X until end of turn, where X is the number of Elves on the battlefield.

Priest of Titania

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

Sylvan Messenger

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Sylvan Messenger enters, 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.