Snakes in Ireland
I'm running a second game in my Fantasy Earth setting for D&D 5. This one set in Ireland and with some pretty hefty character limits due to the prejudices of the campaign Patron (Irish Druids).
Basically, only certain local races allowed, and only Irishmen. Also, Druids won't be recruiting from the cities.
Basically, Patrick the Sainted's Ban on snakes has been broken. The Druids want it re-established. They seem to think it's important.
If the limits presented above aren't an issue for you and the theme interests you, please check out the link above for more details.
Vikings, Frenchmen, and the bloody English need not apply. Nor anyone else, really, that isn't from Ireland. Seriously.