Each player loses a third of their life, then discards a third of the cards in their hand, then sacrifices a third of the creatures they control, then sacrifices a third of the lands they control. Round up each time.

Standstill

When a player casts a spell, sacrifice Standstill. If you do, each of that player's opponents draws three cards.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature, then sacrifices a land.

Tasigur, the Golden Fang

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
{2}{G/U}{G/U}: Mill two cards, then return a nonland card of an opponent's choice from your graveyard to your hand.