When I lived in Hawaii, I learned that geckos are good luck. Like most superstitions, this one makes sense: geckos eat cockroaches, and in Hawaii, they have those big, nasty, American Cockroaches.
In theater, I learned to avoid mentioning, quoting, or becoming otherwise involved in William Shakespeare's cursed play, also known as the Scottish Play.
*some other theater superstitions include a prohibition on whistling in a theater unless it is scripted, the mad, endless protocols on what to wear and how often to wash it, and a variety of backstage beliefs. I could do a thesis on theater superstitions.
I've never lived in Africa, but I understand that that is where the whole not opening an umbrella indoors thing comes from. Umbrellas are more often used as parasols in some parts of Africa, and some indigineous, sun-worshipping religions regard opening an umbrella indoors as a mockery of the sun god.
I have only one superstition to relate from the region in which I now live, but I must refrain from doing so, both to respect this community's limits on appropriate topics of discourse and, more importantly, to avoid offending those readers who subscribe to this particular superstition.