I haven’t heard of the soy sauce thing… hilarious!
My favourites:
Don’t point to the moon or you will bleed from your ears.
Don’t talk about setting up a mouse trap because the mouse will hear it and not go into the trap.
Bonus superstition:
In some places on another continent, there are people that believe that there is gold in the bones of albinos (insert political correct term of people with the feature of refraining to produce melanin). It is not fun being an albino in those places…