Tectonic Instability

Whenever a land enters, tap all lands its controller controls.

City of Solitude

Players can cast spells and activate abilities only during their own turns.

Manabarbs

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

War's Toll

Whenever an opponent taps a land for mana, tap all lands that player controls.
If a creature an opponent controls attacks, all creatures that opponent controls attack if able.

Overabundance

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.

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When Leyline Tyrant dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

Yurlok of Scorch Thrash

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

Citadel of Pain

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.

Horizon Stone

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

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.