I'm trying to think of any specifically german traditions, the lead-pouring oracle comes to mind but I think that's common in other countries as well, right? You melt a small piece of lead and pour it into a bowl of water, and the shape it forms as it cools tells you about your future.
Having a pig is lucky because when you have a pig you'll have food. And a four-leaf clover is lucky because normal clover only has three leaves and you have to be really lucky to find one with four.