In the most blatant LOST shout-out yet, Apollo candy bars, the fictional candy brand which made frequent appearances in LOST, have now arrived in Once Upon a Time‘s Storybrooke:

First, a very quick glimpse in Archie's office

Then we see it again for a split-second longer in front of the entrance to the mine
Another shout-out is the way the entrance to the collapsed mine in Storybrooke looks like the entrance to the Hatch/Swan Station in LOST:

Henry using a flashlight to peer down into the tunnel

Locke and Jack using a torch to peer down into the Hatch

The debris-filled entrance to the mine in Once Upon a Time

The debris-filled entrance to the Swan Station in LOST Season 5 finale ("The Incident")
Anyone notice anything else?