Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mana Flare

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

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Whenever a player taps a land for mana, that player adds one mana of any type that land produced, and Overabundance deals 1 damage to the player.

If you would lose unspent mana, that mana becomes colorless instead.

Vigilance
A player losing unspent mana causes that player to lose that much life.
{1}, {T}: Each player adds {B}{R}{G}.

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.