Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Lich's Tomb

You don't lose the game for having 0 or less life.
Whenever you lose life, sacrifice a permanent for each 1 life you lost. (Damage causes loss of life.)

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Cruel Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Dark Ritual

Cadaverous Bloom

Exile a card from your hand: Add {B}{B} or {G}{G}.

Soul Conduit

{6}, {T}: Two target players exchange life totals.