Jaspera Sentinel

Reach
{T}, Tap an untapped creature you control: Add one mana of any color.

Sol Ring

Fyndhorn Elves

Island

Arbor Elf

Elvish Mystic

Heritage Druid

Tap three untapped Elves you control: Add {G}{G}{G}.

Essence Warden

Whenever another creature enters, you gain 1 life.

Plains

Galadriel, Light of Valinor

Alliance — Whenever another creature you control enters, choose one that hasn't been chosen this turn —
• Add {G}{G}{G}.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Llanowar Elves

Tropical Island

Command Tower

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

Forest

Savannah

Monk of the Open Hand

Flurry of Blows — Whenever you cast your second spell each turn, put a +1/+1 counter on Monk of the Open Hand.