Here is a pretty pastel color palette for Excel with six colors, excluding red, yellow, and green:

json
{
  "palette_name": "Pastel Dreams",
  "colors": [
    {
      "name": "Pastel Blue",
      "hex_code": "
          
          #A4C8E1
       "
    },
    {
      "name": "Pastel Pink",
      "hex_code": "
          
          #F1A7B5
       "
    },
    {
      "name": "Pastel Lavender",
      "hex_code": "
          
          #D5C8E2
       "
    },
    {
      "name": "Pastel Peach",
      "hex_code": "
          
          #F4C4B5
       "
    },
    {
      "name": "Pastel Mint",
      "hex_code": "
          
          #B2E1D4
       "
    },
    {
      "name": "Pastel Lilac",
      "hex_code": "
          
          #E2C6E6
       "
    }
  ]
}

This palette features soft, gentle hues that create a harmonious and calming atmosphere, perfect for a pastel-themed Excel project. Would you like to explore more color palettes or need assistance with anything else?