What are Superstitions about death?

There are thousands, however the more common include;

The inexplicable howling dogs as an omen of coming death

Bees leaving the hives as an omen of the death of the "head of the household"

Covering mirrors in a house where there has been a death, so the spirit of the departed won't get "lost" in them.

Not speaking ill of the dead, as they are closer to the gods and may speak ill of you to them.