Peregrine Drake and Returned Pastcaller on the battlefield.
You control up to five lands that can tap to produce at least ({2} magic symbol) ({U} magic symbol) .
Steps
Activate up to five lands by tapping them, adding at least ({2} magic symbol) ({U} magic symbol) .
Cast Ghostly Flicker by paying ({2} magic symbol) ({U} magic symbol) , blinking Returned Pastcaller and Peregrine Drake.
When Returned Pastcaller and Peregrine Drake enter the battlefield, their abilities trigger.
Resolve the Returned Pastcaller trigger, returning Ghostly Flicker to your hand from your graveyard.
Resolve the Peregrine Drake trigger, untapping up to five lands.
Repeat.
Notes
If you control five lands that can tap to produce at least ({3} magic symbol) ({U} magic symbol) , this combo nets infinite mana, and you may blink any other permanent besides Peregrine Drake.