Port Razer from your graveyard with a memory counter on it as it is an Assassin due to Maskwood Nexus, and then creating a tapped and attacking token copy of each creature you own in exile with a memory counter on it.
Deal combat damage to an opponent using the
Port Razer token.
The
Port Razer token triggers, causing you to untap all creatures you control and to get an additional combat phase after this one.
At the end of your combat phase,
Altaïr Ibn-La'Ahad triggers, exiling the
Port Razer token.
Move to your next combat phase, and declare
Altaïr Ibn-La'Ahad as an attacker.
Altaïr Ibn-La'Ahad triggers, creating a tapped and attacking token copy of each creature you own in exile with a memory counter on it.
Repeat from step 3.
Results
Infinite LTB.
Infinite ETB.
Infinite combat phases.
Infinite untap of creatures you control.
Infinite mana creatures you control can produce.
Infinite combat damage.
Metadata
In 1 deck according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).