Tinybones, Trinket Thief

At the beginning of each end step, if an opponent discarded a card this turn, you draw a card and you lose 1 life.
{4}{B}{B}: Each opponent with no cards in hand loses 10 life.

Umbilicus

At the beginning of each player's upkeep, that player may pay 2 life. If they don't, they return a permanent they control to its owner's hand.

Sygg, River Cutthroat

At the beginning of each end step, if an opponent lost 3 or more life this turn, you may draw a card. (Damage causes loss of life.)

Asylum Visitor

At the beginning of each player's upkeep, if that player has no cards in hand, you draw a card and you lose 1 life.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Forsaken Wastes

Players can't gain life.
At the beginning of each player's upkeep, that player loses 1 life.
Whenever Forsaken Wastes becomes the target of a spell, that spell's controller loses 5 life.

Barbed Wire

At the beginning of each player's upkeep, Barbed Wire deals 1 damage to that player.
{2}: Prevent the next 1 damage that would be dealt by Barbed Wire this turn.

Vile Consumption

All creatures have "At the beginning of your upkeep, sacrifice this creature unless you pay 1 life."

Breathstealer's Crypt

If a player would draw a card, instead they draw a card and reveal it. If it's a creature card, that player discards it unless they pay 3 life.

Copper Tablet

At the beginning of each player's upkeep, Copper Tablet deals 1 damage to that player.