Activate The Third Doctor by paying {1}{U}, blinking it.
When The Third Doctor enters, it and Deadeye Navigator's soulbond ability trigger
Resolve the Deadeye Navigator trigger, repairing it and The Third Doctor.
Resolve the The Third Doctor trigger, creating two Treasure tokens.
Activate both Treasures by tapping and sacrificing them, adding {1}{U}.
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite artifact sacrifice triggers

Infinite creature LTB

Infinite creature ETB

Deadeye Navigator

Adrix and Nev, Twincasters

The Third Doctor

Activate The Third Doctor by paying {1}{U}, blinking it.
When The Third Doctor enters, it and Deadeye Navigator's soulbond ability trigger twice.
Resolve both Deadeye Navigator triggers, repairing it and The Third Doctor.
Resolve both The Third Doctor triggers, creating two Treasure tokens.
Activate both Treasures by tapping and sacrificing them, adding {1}{U}.
Repeat.

Panharmonicon

Activate Emiel the Blessed by paying {1}, blinking The Third Doctor.
When The Third Doctor enters the battlefield, it triggers, creating a Treasure artifact token.
Activate the Treasure by tapping and sacrificing it, adding {1}.
Repeat.

Emiel the Blessed

Training Grounds

Activate Emiel the Blessed by paying {3}, blinking The Third Doctor.
When The Third Doctor enters the battlefield, it triggers twice, and Preston triggers twice if its power is 2 or less or once otherwise.
Resolve the The Third Doctor triggers, creating two Treasure tokens.
Resolve the first Preston trigger, creating a token copy of The Third Doctor that is a 0/1 Illusion.
When the The Third Doctor token enters the battlefield, it triggers twice, creating two Treasure tokens.
Repeat from step 4 for the remaining Preston trigger, if applicable.
Activate three Treasures by tapping and sacrificing them, adding {3}.
Repeat.

Combos with "The Third Doctor"