Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim, Mayhem Dominus. ({R/P} can be paid with either {R} or 2 life.)

Manabarbs

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

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.

Zo-Zu the Punisher

Whenever a land enters, Zo-Zu the Punisher deals 2 damage to that land's controller.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Price of Glory

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

Stoneshaker Shaman

At the beginning of each player's end step, that player sacrifices an untapped land of their choice.

Burning Earth

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

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Pillage

Destroy target artifact or land. It can't be regenerated.

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

Dwarven Miner

{2}{R}, {T}: Destroy target nonbasic land.

Tremble

Each player sacrifices a land of their choice.

Akki Blizzard-Herder

When Akki Blizzard-Herder dies, each player sacrifices a land of their choice.

Iron Myr

Ruby Medallion

Red spells you cast cost {1} less to cast.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

Seething Song

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Dingus Egg

Whenever a land is put into a graveyard from the battlefield, Dingus Egg deals 2 damage to that land's controller.

Krenko's Buzzcrusher

Flying, trample
When Krenko's Buzzcrusher enters, for each player, destroy up to one nonbasic land that player controls. For each land destroyed this way, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.

Volcanic Offering

Destroy target nonbasic land you don't control and target nonbasic land of an opponent's choice you don't control.
Volcanic Offering deals 7 damage to target creature you don't control and 7 damage to target creature of an opponent's choice you don't control.

Heart of Ramos

{T}: Add {R}.
Sacrifice Heart of Ramos: Add {R}.

Sunspine Lynx

Players can't gain life.
Damage can't be prevented.
When Sunspine Lynx enters, it deals damage to each player equal to the number of nonbasic lands that player controls.