ysabetwordsmith mentioned the
Fish Out of Water motif, and I was thinking: "Does it still count as a motif if it's part of every story?"
If you define this as "character dropped into alien setting", then it's not something that happens in every story, true. But if you define it broadly -- "character in new, unfamiliar surroundings/circumstances" -- then practically every story has one. It's usually a character that (a) gets stuff explained to them, in lieu of the reader, and/or (b) sets the plot in motion by shaking up/exploring the existing environment. Some examples of the broadly-defined "Fish Out of Water" from my recent reading:
* A Study in Scarlet: Dr Watson (unfamiliar with detective work)
* Master and Commander : Stephen Maturin (unfamiliar with the seafaring life)
* Emma : Frank Churchhill (new to the neighborhood)
* The Demon's Lexicon : Mae and Jamie (unfamiliar with magic)
* The Stepsister Scheme : Danielle (unfamiliar with fairy and the whole princess-as-secret-agent business until introduced to the other princesses)
* Blameless : Alexia (travelling in France and Italy, unfamiliar settings to her)
* The Lies of Locke Lamora: Locke (introduced to the Gentlemen Bastards and their lifestyle in the extended flashbacks)
* The Hundred Thousand Kingdoms : narrator (unfamilar with palace setting)
Honestly, it's hard to think of a series without a Fish. Sometimes sequels don't really have one -- everyone is used to the setting by then, including the reader who acclimatized in the earlier books. Soulless, interestingly, despite being the first book, doesn't really seem to have a fish as a major character. I could argue for Alexia and supernatural culture, I suppose, but she's not really immersed in the unfamiliar here; she's got some prior experience with it, and she's dealing with familiar surroundings frequently as well. Anyway, I think it's possible to write a story with characters who all belong to their current environment, but my experience is that even with books set in contemporary, non-fantasy-or-sf settings, it's pretty rare.
It's still a motif, though -- not every character fits the type, even if nearly every story has a character who does.