Licia, Sanguine Tribune

This spell costs {1} less to cast for each 1 life you gained this turn.
First strike, lifelink
Pay 5 life: Put three +1/+1 counters on Licia, Sanguine Tribune. Activate only during your turn and only once each turn.

Exquisite Blood

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

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Sanguine Bond

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