It depends on the religion and who you are talking about. In Sumerian religion Inanna or Ishtar needed a crown, rings in her ears, beads, toggle pins, girdle birthstone, bangles, and garment. Which was all taken off when entering each gate. The reason for this was to make her weaker. Ishtar got her items back for they were magickal and the Gods helped her get out of the underworld. There is a story were Gilgamesh attains objects from the underworld, which is another Sumerian or Mesopotamia story. A lot of Gods, Goddesses, Demi-Gods, Entities, and Heroes all had to have items to go to the underworld or had to attain items from the underworld. The underworld would be a place depicted as looking the same as earth. Other depictions would be of fire, monsters, and total darkness. There is stories that talk about civilizations living under ground and having cities. I would look at each hero and type in what items they used. It should be really simple because there are a lot of stories involving going into the underworld.