Brass's Bounty, creating a Treasure token for each land you control.
Holding priority, activate
Phyrexian Altar by sacrificing
Lutri, adding one mana of any color.
Activate four Treasures by tapping and sacrificing them, adding one mana of each color that you didn't add in step 5.
Activate
Horde of Notions by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , causing you to cast
Lutri from your graveyard without paying its mana cost.
Repeat from step 3.
Notes
You can start the combo instead at step 7 if
Lutri is in your graveyard. This changes the mana needed to ({6} magic symbol) ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Results
Infinite ETB.
Infinite LTB.
Infinite Treasure tokens.
Infinite colored mana.
Infinite death triggers.
Infinite magecraft triggers.
Infinite recursion of Elemental cards in your graveyard.