Here is a 13-color palette designed for a timeline sign:

json
{
  "palette_name": "Timeline Sign Colors",
  "colors": [
    {
      "name": "Midnight Blue",
      "hex_code": "
                            
                            #003366
                        "
    },
    {
      "name": "Sky Blue",
      "hex_code": "
                            
                            #87CEEB
                        "
    },
    {
      "name": "Sunshine Yellow",
      "hex_code": "
                            
                            #FFD700
                        "
    },
    {
      "name": "Coral",
      "hex_code": "
                            
                            #FF7F50
                        "
    },
    {
      "name": "Light Green",
      "hex_code": "
                            
                            #90EE90
                        "
    },
    {
      "name": "Tomato",
      "hex_code": "
                            
                            #FF6347
                        "
    },
    {
      "name": "Lavender",
      "hex_code": "
                            
                            #E6E6FA
                        "
    },
    {
      "name": "Peach",
      "hex_code": "
                            
                            #FFDAB9
                        "
    },
    {
      "name": "Slate Gray",
      "hex_code": "
                            
                            #708090
                        "
    },
    {
      "name": "Crimson",
      "hex_code": "
                            
                            #DC143C
                        "
    },
    {
      "name": "Medium Orchid",
      "hex_code": "
                            
                            #BA55D3
                        "
    },
    {
      "name": "Gold",
      "hex_code": "
                            
                            #FFD700
                        "
    },
    {
      "name": "Turquoise",
      "hex_code": "
                            
                            #40E0D0
                        "
    }
  ]
}

This palette features a range of colors that can effectively represent different points or events on a timeline, providing clarity and visual appeal. Would you like to know more about how to use these colors, or do you have specific themes or events you need to represent?