Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Seething Song

Burning-Tree Emissary

When Burning-Tree Emissary enters, add {R}{G}.

Rosheen Meanderer

{T}: Add {C}{C}{C}{C}. Spend this mana only on costs that contain {X}.

Biorhythm

Each player's life total becomes the number of creatures they control.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Copperline Gorge

Copperline Gorge enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {G}.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.