Here is a darker monochromatic blue color palette featuring navy and its shades:

json
{
  "palette_name": "Dark Monochromatic Blue",
  "colors": [
    {
      "name": "Light Navy",
      "hex_code": "
          
          #001F3F
       "
    },
    {
      "name": "Navy",
      "hex_code": "
          
          #001F5B
       "
    },
    {
      "name": "Dark Navy",
      "hex_code": "
          
          #000080
       "
    },
    {
      "name": "Midnight Blue",
      "hex_code": "
          
          #191970
       "
    },
    {
      "name": "Steel Blue",
      "hex_code": "
          
          #4682B4
       "
    },
    {
      "name": "Dark Slate Blue",
      "hex_code": "
          
          #483D8B
       "
    }
  ]
}

This palette emphasizes darker shades of blue, including navy and its deeper variations, providing a bold and sophisticated color scheme. Would you like to see other shades or perhaps a different color family?