Yavimaya, Cradle of Growth

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

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Urborg, Tomb of Yawgmoth

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

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Mana Web

Whenever a land an opponent controls is tapped for mana, tap all lands that player controls that could produce any type of mana that land could produce.

Plow Under

Put two target lands on top of their owners' libraries.

Azusa, Lost but Seeking

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

Spreading Algae

Enchant Swamp
When enchanted land becomes tapped, destroy it.
When Spreading Algae is put into a graveyard from the battlefield, return Spreading Algae to its owner's hand.