Here is a color palette based on the query for a header blue color:

json
{
  "palette_name": "Header Blue Palette",
  "colors": [
    {
      "name": "Deep Sky Blue",
      "hex_code": "
          
          #00BFFF
       "
    },
    {
      "name": "Steel Blue",
      "hex_code": "
          
          #4682B4
       "
    },
    {
      "name": "Dodger Blue",
      "hex_code": "
          
          #1E90FF
       "
    },
    {
      "name": "Light Sky Blue",
      "hex_code": "
          
          #87CEFA
       "
    },
    {
      "name": "Sky Blue",
      "hex_code": "
          
          #87CEEB
       "
    }
  ]
}

This palette features various shades of blue that can be used effectively for headers, providing a fresh and engaging look. Would you like to explore more about how to utilize these colors in your design?