Dual land

Dual lands or duals is common slang for any nonbasic land that produces two colors of mana, particularly the ten original rare lands printed from Alpha to Revised.

Allied colored

 * Tundra (/)
 * Underground Sea (/)
 * Badlands (/)
 * Taiga (/)
 * Savannah (/)

Enemy colored

 * Scrubland (/)
 * Volcanic Island (/)
 * Bayou (/)
 * Plateau</c> (/)
 * Tropical Island</c> (/)

Legacy
Since then, "dual land" has also come to refer to any land that can produce two colors of mana. Dual lands are often highly sought-after and fetch high prices on the secondary market.

Popular dual land cycles have been printed in numerous sets, including:

There are also a few notable "triple lands" cycles that produce three colors of mana; a cycle of shard-colored triple lands was printed in Shards of Alara, and two cycles of of wedge-colored triple lands have been printed: one in in Khans of Tarkir, the other in Ikoria: Lair of Behemoths.

Trivia

 * Volcanic Island</c> was not printed in Alpha through internal error. This oversight was corrected in Beta.
 * Plateau</c> has an alternate art in the Revised version due to lost and corrupted art.
 * All original dual lands received new art for Magic Online.