Mortuary + Cauldron Familiar + Bolas's Citadel + Bloodthrone Vampire Combo

Cauldron Familiar in hand or in your library (Cauldron Familiar on top of your library in your library).

All other permanents on the battlefield.

You have a life total of at least 2 if Cauldron Familiar is on top of your library.

if Cauldron Familiar is in your hand available

Cast Cauldron Familiar either from your hand or from the top of your library by paying or 1 life respectively.

When Cauldron Familiar enters, it triggers, causing each opponent to lose 1 life and you to gain 1 life.

Activate Bloodthrone Vampire by sacrificing Cauldron Familiar.

When Cauldron Familiar dies, Mortuary triggers, putting Cauldron Familiar from your graveyard onto the top of your library.

Resolve the Bloodthrone Vampire ability.

Repeat.

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite death triggers

Infinite lifegain triggers

Infinite lifeloss

Infinite storm count