Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Sythis, Harvest's Hand

Whenever you cast an enchantment spell, you gain 1 life and draw a card.

Solemnity

Players can't get counters.
Counters can't be put on artifacts, creatures, enchantments, or lands.

Phyrexian Unlife

You don't lose the game for having 0 or less life.
As long as you have 0 or less life, all damage is dealt to you as though its source had infect. (Damage is dealt to you in the form of poison counters.)

Enchantress's Presence

Whenever you cast an enchantment spell, draw a card.

Sandsteppe Citadel

This land enters tapped.
{T}: Add {W}, {B}, or {G}.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.