The uncommon Karoo lands from Visions are a cycle of five lands, one for each color of mana, which could add and one mana of that respective color to its controller's mana pool. However, when it came in to play, an untapped land with the corresponding basic land type had to be returned to its owner's hand.
Cards in the Visions cycle
Ravnica block cycle
The ten common Karoo lands of the Ravnica block (also called 'Bounce lands', because they require you to return (bounce) a land back to your hand) each correspond to the ten guilds of Ravnica, which in turn each refer to the ten different pairs of colors. Each of the lands could produce one mana of each color the guild represents. However, a land has to be returned to its owner's hand, so if the Karoo land is the only land in play at the time, it will automatically be returned to its owner's hand.
Cards in the Ravnica block cycle
Allied-colored Karoo lands
Enemy-colored Karoo lands
|Common types of nonbasic lands|
|No colors of mana/no mana: Fetch lands|
|One colors of mana: Sac lands|
|Two colors of mana: Dual lands • Filter lands • Gates • Karoo lands • Pain lands • Sac lands • Shock lands • Slow lands • Taplands •|
|Three colors of mana: Lairs • Triple lands|