The original folktale of Kaguya hime, the Tale of the bamboo cutter ( en.wikipedia.org/wiki/The_Tale… had Kaguya as the owner of five legendary items (actually she had her marriage suitors to bring her the items as a rather impossible request)
Here is my version of what these items could represent on the Naruto world as treasures possessed by Kaguya herself:
Jeweled branch of Mount Hōrai: A staff that help her to cast chakra in form of powerful magic - made from the God tree branches. I used the sun/moon symbolism here for the balance of power coming from the God tree.
Buddha's stone begging bowl: A treasure with mystical properties related to sealing of souls and/or talking and summoning the dead.
Jewel of dragon scale: A scaled necklace with a dragon pearl at the center. A jewel made to summon thunders from the sky.
The swallow's cowrie: A giant golden cowrie, which could be used as a musical blowing instrument to cast illusions and tricks.
Legendary fire rat's robe: A robe used to cover it's user in fire element, turning them virtually untouchable and invincible - however only those with very strong chakra are able to wear it without burning themselves.
*As she is basically a goddess, it was particularly hard to think about items that wouldn't be futile for someone of her caliber... I tried to go for a more mystical/spiritual concept since it would suit her - also the design was freely done on my style, so I never tried to make them visually suitable for the Naruto manga style.