Here is a pastel rainbow color palette that combines soft, light colors, making it visually appealing while still maintaining the essence of a rainbow. This palette should be easier on the eyes but more vibrant than a muted palette.

json
{
  "palette_name": "Pastel Rainbow Years in Excel",
  "colors": [
    {
      "name": "Pastel Red",
      "hex_code": "
          
          #FFB3B3
       "
    },
    {
      "name": "Pastel Orange",
      "hex_code": "
          
          #FFCC99
       "
    },
    {
      "name": "Pastel Yellow",
      "hex_code": "
          
          #FFFF99
       "
    },
    {
      "name": "Pastel Green",
      "hex_code": "
          
          #B3FFB3
       "
    },
    {
      "name": "Pastel Blue",
      "hex_code": "
          
          #99CCFF
       "
    },
    {
      "name": "Pastel Indigo",
      "hex_code": "
          
          #CC99FF
       "
    },
    {
      "name": "Pastel Violet",
      "hex_code": "
          
          #EAB8E4
       "
    },
    {
      "name": "Pastel Pink",
      "hex_code": "
          
          #FFB3E6
       "
    },
    {
      "name": "Pastel Teal",
      "hex_code": "
          
          #99FFFF
       "
    },
    {
      "name": "Pastel Lavender",
      "hex_code": "
          
          #D3B2E6
       "
    }
  ]
}

This pastel rainbow palette offers a lovely balance of soft colors suitable for representing each year in your Excel sheets. Would you like to make any adjustments or explore further options?