Crystal Stars

The Crystal Stars are seven powerful star-shaped gemstone artifacts from the Mushroom Kingdom, debuting in Paper Mario: The Thousand-Year Door. They are from the town of Rougeport, and serve as keys to open the Thousand-Year Door itself. Mario, with serveral partners, journeys across the country of Rougeport in order to find the Crystal Stars and save the world from the Shadow Queen.

In Mario & Sonic: Worlds in Danger
The Crystal Stars appear in Jmkrebs30's flash series Mario and Sonic Worlds In Danger, as two of the main plot points of the series, alongside the Chaos Emeralds. Bowser and Dr. Eggman are trying to collect the Emeralds and Stars in order to merge the Mushroom World and Mobius together to create a galactic evil empire. The heroic Super Mario and Sonic the Hedgehog are trying to collect the Emeralds and Stars in order to save the two worlds from the two tyrants' rule.