For questions about sources of mana, balancing colors of mana, and the amount of mana sources to include in a deck.

Most non land cards in Magic: the Gathering have a mana cost to play, the manabase provides the resources to pay these costs. It is made up primarily of lands. As Magic the Gathering has 5 colors of mana, the balance between lands that make these different colors and have other useful, or detrimental, effects are a big part of what makes that deck effective.