Triple land

Triple lands (or Tri lands) is common slang for any nonbasic land that produces three colors of mana.

Original triple lands
The earliest triple land cycles from Homelands which produces three colors of mana conditionally as follows:
 * undefined: Add.
 * ,undefined: Add M.
 * ,undefined: Add N or O.

where N and O are the allied colors of M.
 * Aysen Abbey
 * Wizards' School
 * Castle Sengir
 * Koskun Keep
 * An-Havva Township

Tri-color taplands
There are some tri-colored tapland cycles. The ability to produce three colors of mana is often compensated with entering the battlefield tapped.
 * Sac lands from Invasion that can be sacrificed for one of each of that color's allied colors.
 * Shard-colored taplands from Shards of Alara
 * Wedge-colored taplands from Khans of Tarkir

Tricycle lands

 * Ikoria: Lair of Behemoths introduced wedge-colored taplands with basic land types and cycling

Lairs
Planeshift lairs that must be sacrificed when it comes into play unless return a non-Lair land to owner's hand and can be tapped for one mana of any of three colors.

Tri-color tribal land
There are two tribal lands printed that are capable of generating exactly three colors of mana:


 * Murmuring Bosk from Morningtide, associated with Treefolk. It has the basic land type Forest, and can come in untapped if a Treefolk is revealed from hand on entry. In addition, it can tap for or  at the cost of 1 damage.
 * Tournament Grounds from Throne of Eldraine, associated with Knights. It can tap for ,, or only for Knight or Equipment spells, but also can tap for.