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
It is bad luck to put new shoes on a bed (or a table) (comes from the tradition of dressing a corpse in new clothes and shoes and laying them out so everyone can give their respects) - (UK)
57
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
If you catch a falling leaf on the first day of autumn you will not catch a cold all winter.
394
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
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
Collect seven or nine different flowers on midsummer eve and place them under your pillow and it is said that you will dream of your future spouse. (Sweden)
463