Rydia, Summoner of Mist + There and Back Again + Barbara Wright + Hex Parasite + High Alert
Infinite Mana: Infinite LTB, Infinite ETB, Infinite colored mana, Infinite death triggers, Infinite Treasure tokens, Infinite untap of creatures you control, Infinite mana creatures you control can produce
At the beginning of your precombat main phase, There and Back Again triggers, putting a lore counter on it and triggering its third chapter ability, creating a 6/6 Smaug legendary creature token and sacrifice There and Back Again.
Activate Rydia by paying {5} and tapping it, returning There and Back Again from your graveyard to the battlefield with a finality counter on it. As There and Back Again enters the battlefield, choose to have it enter with three lore counters due to its read-ahead ability.
There and Back Again's third chapter ability triggers. Holding priority, activate Hex Parasite by paying {1}{B/P}, removing the finality counter from There and Back Again.
Resolve the There and Back Again trigger, creating a 6/6 Smaug legendary creature token and sacrifice There and Back Again.
Put a Smaug token into your graveyard due to the legend rule, triggering its ability, creating fourteen Treasure tokens.
Activate eleven Treasures by tapping and sacrificing them, adding {8}{W}{U}{B}.
Activate High Alert by paying {2}{W}{U}, untapping Rydia.
Repeat from step 2.
Cards: Rydia, Summoner of Mist, There and Back Again, Barbara Wright, Hex Parasite, High Alert