Polluted Bonds

Whenever a land an opponent controls enters, that player loses 2 life and you gain 2 life.

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Spellshock

Whenever a player casts a spell, Spellshock deals 2 damage to that player.

No Mercy

Whenever a creature deals damage to you, destroy it.

Tainted Aether

Whenever a creature enters, its controller sacrifices a creature or land of their choice.

Burning Sands

Whenever a creature dies, that creature's controller sacrifices a land of their choice.

Pain Magnification

Whenever an opponent is dealt 3 or more damage by a single source, that player discards a card.

Mogis, God of Slaughter

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature of their choice.