Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Great Forest Druid

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Elvish Mystic

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Arbor Elf

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath gets +1/+1 for each unspent green mana you have.

Karametra's Acolyte

{T}: Add an amount of {G} equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Llanowar Elves

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.