The superstitious symbolism of a black cat crossing one's path is dependent upon culture: some cultures consider this a sign of impending bad luck, while some cultures consider this a sign of impending good luck.
75
A single magpie is considered a sign of bad luck. A Guide to the Scientific Knowledge of Things Familiar recites an old proverb concerning the incidence of bad weather when magpies forage alone and a possible scientific explanation for this.
49
When you speak of bad luck, it is said that one should always knock on wood. Also knocking when speaking of good luck apparently helps with having good luck. This is an old Celtic tradition related to belief of wood spirits.
208
In some parts of England, rum is used to wash a baby's head for good luck.
71
It's bad luck to leave a house through a different door than the one used to come into it.
143
Placing keys on a table is considered unlucky. (Sweden)
3
According to an age old custom, carrying a dead shrew in your pocket wards off rheumatism!
24
Pirates believed that piercing the ears with such precious metals as silver and gold improved one's eyesight.
131