You have at least one legendary creature card exiled with a memory counter on it.
Steps
Declare Altaïr as an attacker. Altaïr triggers, exiling
Éomer from your graveyard with a memory counter on it, and then creating a tapped and attacking token copy of each card you own that is exiled with a memory counter on it.
Activate
Bartolomé del Presidio by sacrificing another legendary creature token except
Éomer.
When the creature dies,
Éomer triggers, untapping all creatures you control and causing you to get an additional combat phase after this one.
Resolve the
Bartolomé del Presidio ability.
Repeat during each combat phase.
Results
Infinite creature LTB.
Infinite creature ETB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite combat phases.
Infinite +1/+1 counters on a creature.
Metadata
Bracket tag
ExhibitionBracket 1+
For any deck
1
2
3
4
5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.