Manland
"Manland" (also "man-land") is a slang term referring to any land card that can inherently turn itself into a creature.
The earliest and most famous of the "manlands" is Mishra's Factory. Mishra's Factory was first printed in Antiquities with four different illustrations by Kaja and Phil Foglio, one for each season: Spring, Summer, Fall (Autumn), and Winter. The Fall version was reprinted in 4th Edition. The card is also notable for collaboratively working with other copies of the same card.
The next "manland" didn't come along until Tempest; Stalking Stones was unusual as it became a creature permanently. It was reprinted in Mirrodin.
Urza's Legacy brought a cycle of these lands, each of which came into play tapped; this is when the nickname manlands was coined. When the cycle was reprinted in 10th Edition, the lands were given creature types when they used their abilities to turn into creatures. All of the lands turn into creatures of the color of mana the land can produce for 
C, though the size and abilities of the creatures vary.
Another special form of manland was featured in Future Sight with Dryad Arbor, a card that is both a land and a creature without having an activated ability to turn itself into a creature. It is also the only land that isn't colorless.
Worldwake is a set with a distinct theme of making lands into creatures. As such, it features six lands that turn into creatures. Five of which are also Taplands, lands that enter the battlefield tapped and produce one mana of either color of an allied pair. The activation cost contains both colors and varies from card to card as does the size and abilities of the creature, though all of them are Elemental creatures of both colors the land can produce.
- Celestial Colonnade (
/
) - Creeping Tar Pit (/
) - Lavaclaw Reaches (/
) - Raging Ravine (/
) - Stirring Wildwood (/)
The set also features Dread Statuary which does not enter the battlefied tapped but only taps for colorless mana with a colorless activation cost to turn itself into a Golem artifact creature.
Other Manlands have been printed occasionally if the set thematically permitted.
- Nantuko Monastery in Judgment.
- Blinkmoth Nexus in Darksteel as an homage to Mishra's Factory.
- Svogthos, the Restless Tomb in Ravnica: City of Guilds.
- Mutavault in Morningtide.
- Inkmoth Nexus in Mirrodin Besieged.
There are also a variety of cards that can turn lands into creatures, either permanently or temporarily. However these are not lands and therefore are not considered manlands. Examples would be Living Lands from Alpha, the Genju Cycle from Betrayers of Kamigawa and the Zendikon Cycle of Worldwake.