Yes, but also no.

By definition, a superstition that is valid is not a superstition. "Red sky in the morning, sailor take warning" is usually not called a superstition, because it is a good heuristic. "13 is unlucky" is called a superstition because it is not useful.

Things that might be a 'useful superstition' include:

• An apple a day keeps the doctor away.
• Garlic protects from evil spirits [if read 'sickness'].
• After receiving a container of food, the container should never be returned empty.
• Meditation makes you healthy and wise.
• Going to church makes you a good person. [networking, community, charity]
• Being bad will send you to hell.
• Being bad will reduce your chances of Santa bringing you toys.

Obviously, the truth value of these is variable and often requires a generous interpretation. Also, some (all?) of these are only useful to people who want easy rules, indicating that they aren't really LessWrong types.