Nylea's Presence

Enchant land
When Nylea's Presence enters the battlefield, draw a card.
Enchanted land is every basic land type in addition to its other types.

Yavimaya, Cradle of Growth

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

Lush Growth

Enchant land
Enchanted land is a Mountain, Forest, and Plains.

Eladamri, Lord of Leaves

Other Elf creatures have forestwalk. (They can't be blocked as long as defending player controls a Forest.)
Other Elves have shroud. (They can't be the targets of spells or abilities.)

Mystic Compass

{1}, {T}: Target land becomes the basic land type of your choice until end of turn.

Gaea's Liege

As long as Gaea's Liege isn't attacking, its power and toughness are each equal to the number of Forests you control. As long as Gaea's Liege is attacking, its power and toughness are each equal to the number of Forests defending player controls.
{T}: Target land becomes a Forest until Gaea's Liege leaves the battlefield.

Thelonite Monk

{T}, Sacrifice a green creature: Target land becomes a Forest. (This effect lasts indefinitely.)

Song of the Dryads

Enchant permanent
Enchanted permanent is a colorless Forest land.

Deepwood Elder

{X}{G}{G}, {T}, Discard a card: X target lands become Forests until end of turn.