Lost in the Woods

Whenever a creature attacks you or a planeswalker you control, reveal the top card of your library. If it's a Forest card, remove that creature from combat. Then put the revealed card on the bottom of your library.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Yavimaya Gnats

Multani, Yavimaya's Avatar

Reach, trample
Multani, Yavimaya's Avatar gets +1/+1 for each land you control and each land card in your graveyard.
{1}{G}, Return two lands you control to their owner's hand: Return Multani from your graveyard to your hand.

Birds of Paradise

Forest

Llanowar Elves

Sol Ring

Summer Bloom

You may play up to three additional lands this turn.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Fyndhorn Elves

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Yavimaya Granger

Echo {2}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Yavimaya Granger enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Yavimaya Hollow

{T}: Add {C}.
{G}, {T}: Regenerate target creature.

Omnath, Locus of Mana

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

Explore

You may play an additional land this turn.
Draw a card.

Gauntlet of Power

As Gauntlet of Power enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.