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
Opening an umbrella indoors is said to result in 21 days of bad luck. Some traditions hold that it is only bad luck if the umbrella is placed over the head of someone while indoors.
75
Placing keys on a table is considered unlucky. (Sweden)
3
If you catch a falling leaf on the first day of autumn you will not catch a cold all winter.
394
Once a wedding ring has been placed on the finger, it is considered bad luck to remove it.
117
Some motorcycle enthusiasts hang a biker's bell from a portion of their bike to protect themselves from evil road spirits.
64
At times, a horseshoe may be found above doorways. When positioned like a regular 'U' it supposedly collects luck. However, when it is positioned like an upside-down 'U' the luck supposedly drains.
78
Before traveling a person should, apparently, sit on their luggage. (Russian)
117