Have

Elvish Mystic

Rishkar, Peema Renegade

When Rishkar, Peema Renegade enters, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

Timberwatch Elf

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

Immaculate Magistrate

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

Llanowar Elves

Copperhorn Scout

Whenever Copperhorn Scout attacks, untap each other creature you control.

Don't Have

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.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

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.

Lys Alana Huntmaster

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

Forest

Elvish Guidance

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

Imperious Perfect

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

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

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.

Sol Ring

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Elvish Visionary

When Elvish Visionary enters, draw a card.

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.

Path of Ancestry

Path of Ancestry enters 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.)

Case of the Trampled Garden

When this Case enters, distribute two +1/+1 counters among one or two target creatures you control.
To solve — Creatures you control have total power 8 or greater. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you attack, put a +1/+1 counter on target attacking creature. It gains trample until end of turn.