Priest of Titania

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

Overrun

Creatures you control get +3/+3 and gain trample until end of turn.

Drove of Elves

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

Shaman of the Pack

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

Essence Warden

Whenever another creature enters the battlefield, you gain 1 life.

Elvish Vanguard

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

Haunted Mire

({T}: Add {B} or {G}.)
Haunted Mire enters the battlefield tapped.

Herald's Horn

As Herald's Horn enters the battlefield, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

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.

Timberwatch Elf

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

Sol Ring

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (A creature with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Jungle Hollow

Jungle Hollow enters the battlefield tapped.
When Jungle Hollow enters the battlefield, you gain 1 life.
{T}: Add {B} or {G}.

Pride of the Perfect

Arcane Signet

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

Command Tower

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Llanowar Elves

Elvish Promenade

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

Fyndhorn Elves

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.