From Minecraft Wiki
Pyramid or pyramids may refer to:
Desert temple - Sandstone structures that generate in desert biomes, containing chests with loot in them as well as a TNT trap
Brick pyramid - Large pyramid-shaped brick structures that only existed in Infdev and are now removed from the game.
Beacon pyramid - The structure that the player must build with blocks of gold, iron, emerald, or diamond to activate a beacon.