I may not know all of them, but I have encountered many of them. Here is a list:
1. If you are going to move, never clean the house you are moving out of. If you clean the house, you take the bad spirits with you.
2. Never write someone’s name in red. You only write the name of a dead person in red.
3. Never put your chopsticks straight up and down in your rice bowl because that means someone is dead. The Japanese have this superstition too. Lay your chopsticks on the side of your bowl.
4. Eat seaweed soup on your birthday because it is healthy. The person who makes you seaweed soup on your birthday is wishing you a long life.
5. Never eat seaweed soup or anything slippery before a test because if you do, the test answers will slip away from you, and you will do badly on the test.
6. Eat sticky things around test time so the answers will stick with you.
7. Eat seaweed soup while you are pregnant so when you go into labor, the baby will slip out easily.
8. Pigs bring good luck.
9. If you get into an elevator in S. Korea, many of them don’t have the fourth floor marked. If it is marked, it is marked with an F rather than the number four. The number four is considered unlucky in S. Korea.
10. If you want to wish someone a long life, give them toilet paper because it is long and all wrapped around the roll.
11. If you want to wish someone riches give them cooking oil.
12. If you want someone to go away and leave you alone, give them shoes so they can walk away. If you don’t want them to leave, never give them shoes.
There are probably more superstitions, but those are the ones I can think of right now.