Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 1 damage to any creature an opponent controls.
The creature dies as a state-based action due to Deathbringer Thoctar's deathtouch.
Deathbringer Thoctar triggers, putting a +1/+1 counter on itself.
Repeat as desired.
You may also repeat this combo whenever a creature enters the battlefield under an opponent's control.

Destroy all creatures opponents control

Destroy any creature that enters the battlefield under an opponent's control

Deathbringer Thoctar

Archetype of Finality

Cast Dread Slaver by paying {3}{B}{B}.
Dread Slaver enters the battlefield, triggering Warstorm Surge, causing Dread Slaver to deal three damage to itself and die due to its deathtouch ability.
Dread Slaver dies, returning itself from your graveyard to the battlefield.
Repeat from step 2.

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Dread Slaver

Warstorm Surge

Kill Dread Slaver.
When Dread Slaver dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
When Dread Slaver enters the battlefield, Flayer of the Hatebound triggers, causing Dread Slaver to deal damage to itself equal to its power.
Dread Slaver dies as a state-based action due to its deathtouch.
Dread Slaver triggers, returning itself from your graveyard to the battlefield.
Repeat from step 3.

Flayer of the Hatebound

Mikaeus, the Unhallowed

Cast Dread Slaver by paying {3}{B}{B}.
Dread Slaver enters the battlefield, triggering Pandemonium, causing Dread Slaver to deal three damage to itself and die due to its deathtouch ability.
Dread Slaver dies, returning itself from your graveyard to the battlefield.
Repeat from step 2.

Pandemonium

Cast Dread Slaver by paying {3}{B}{B}.
When Dread Slaver enters the battlefield, Be'lakor's second ability triggers, causing Dread Slaver to deal damage equal to its power to itself.
Dread Slaver dies as a state-based action due to its deathtouch.
Dread Slaver triggers, returning itself from your graveyard to the battlefield.
Repeat from step 2.

Be'lakor, the Dark Master

Conspiracy

Xenograft

Arcane Adaptation

Maskwood Nexus

Place a counter on a permanent or player.
All Will Be One triggers, dealing 1 damage to an opponent.
Vraska triggers, putting a +1/+1 counter on All Will Be One.
Repeat from step 2.

Combos with "Archetype of Finality"