Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Kodama of the East Tree

Reach
Whenever another permanent enters the battlefield under your control, if it wasn't put onto the battlefield with this ability, you may put a permanent card with equal or lesser mana value from your hand onto the battlefield.
Partner (You can have two commanders if both have partner.)

Sol Ring

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.

Llanowar Elves

Elvish Mystic

Fyndhorn Elves

Cultivate

Song of the Dryads

Enchant permanent
Enchanted permanent is a colorless Forest land.

Birds of Paradise

Arcane Signet

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

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.