Chakotay's medicine bundle.
A medicine bundle is a bag or blanket filled with a few, very personal items used in various Native American rituals.
Chakotay's medicine bundle contained a Blackbird's wing, a ceremonial CHAH-mooz-ee stone and his Akoonah wrapped in animal skins. In 2371, he used it to help Captain Janeway find and contact her animal guide. (VOY: "The Cloud")
Chakotay later used his medicine bundle when performing the pakra, to honor the anniversary of his father's death. (VOY: "Initiations")
- He apparently had a spare medicine bundle, as it didn't seem to be beamed down to the planet with him when the shuttle was later destroyed.
Apocrypha
In the non-canon "The Hologram's Handbook" by Robert Picardo, he tells the story of the Doctor creating his own medicine bundle with Chakotay's guidance.