- Indigo dye: This natural dye is derived from the leaves of the Indigofera tinctoria plant and has been used for centuries to create a deep blue color in fabrics.
- Blue denim: The traditional blue color of denim jeans is achieved using indigo dye.
- Indigo bunting: A small songbird native to North America with bright blue plumage.
- Blueberries: These small, dark-colored berries are often associated with the color indigo.
- Blue morpho butterfly: A tropical butterfly known for its vibrant blue wings.
- Indigo flowers: Various flowers, such as delphiniums, hyacinths, and some irises, can have indigo-colored blooms.
- Lapis lazuli: A deep blue semi-precious stone often used in jewelry and decorative objects.
- Night sky: On a clear night, the sky can appear indigo due to the scattering of sunlight by particles in the atmosphere.