To complement the colors #d7ddeb (soft lavender blue) and #fff71d (bright lemon yellow), I recommend adding #ff6f61 , a warm coral pink. This color adds a vibrant pop that beautifully contrasts with both the soft lavender blue and the bright lemon yellow while maintaining a cheerful and lively aesthetic.

Here is the updated color palette in JSON format:

json
{
  "palette_name": "Cheerful Contrast",
  "colors": [
    {
      "name": "Soft Lavender Blue",
      "hex_code": "
                            
                            #d7ddeb
                        "
    },
    {
      "name": "Bright Lemon Yellow",
      "hex_code": "
                            
                            #fff71d
                        "
    },
    {
      "name": "Warm Coral Pink",
      "hex_code": "
                            
                            #ff6f61
                        "
    }
  ]
}

This palette creates a joyful and energetic combination, where the soft lavender blue provides a gentle foundation, the bright lemon yellow brings a sunny brightness, and the warm coral pink adds a delightful vibrancy. Would you like to explore more color options or different themes?