Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Bello, Bard of the Brambles

During your turn, each non-Equipment artifact and non-Aura enchantment you control with mana value 4 or greater is a 4/4 Elemental creature in addition to its other types and has indestructible, haste, and "Whenever this creature deals combat damage to a player, draw a card."

Sol Ring

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Dawn's Reflection

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional two mana in any combination of colors.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.