({1} magic symbol) ({R} magic symbol) ({W} magic symbol) ({B} magic symbol) plus enough mana to pay for commander tax, if applicable, or an additional ({R} magic symbol) , ({W} magic symbol) or ({B} magic symbol) if you haven't cast Jirina from the command zone this game available.
Steps
Cast Jirina from the command zone by paying ({1} magic symbol) ({R} magic symbol) ({W} magic symbol) ({B} magic symbol) plus commander tax, if applicable.
When Jirina enters the battlefield, it and Mana Echoes trigger.
Resolve the Jirina trigger, creating a 1/1 Human Soldier creature token for each time you've cast Jirina from the command zone this game.
When the Human Soldiers enter the battlefield, Mana Echoes triggers that many times.
Resolve the first Mana Echoes trigger, adding ({C} magic symbol) for each Human and Soldier you control.
Repeat step 5 for each remaining Mana Echoes trigger created in steps 2 and 4.
Activate Bartolomé del Presidio twice by sacrificing Jirina and a Human Soldier.
Choose to return Jirina to the command zone from your graveyard.
When Jirina and the Human Soldier die, Pitiless Plunderer triggers twice, creating two Treasure tokens.
Holding priority, if you control a Human Soldier, activate Bartolomé del Presidio by sacrificing a Human Soldier.
If you sacrificed a Human Soldier this way, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Bartolomé del Presidio abilities from steps 7 and 10, putting three +1/+1 counters on it.
Activate up to three Treasures by tapping and sacrificing them, adding any combination of ({R} magic symbol) , ({W} magic symbol) and ({B} magic symbol) .
Repeat.
Results
Infinite LTB.
Infinite ETB.
Infinite colored mana.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite colorless mana.
Infinite storm count.
Infinite creature tokens.
Infinite Treasure tokens.
Infinite commander casts.
Infinite +1/+1 counters on Bartolomé del Presidio.