Here is a darker gray theme color palette:

{
  "palette_name": "Darker Gray Theme",
  "colors": [
    {
      "name": "Jet Black",
      "hex_code": "
                            
                            #000000
                        "
    },
    {
      "name": "Raven Gray",
      "hex_code": "
                            
                            #1C1C1C
                        "
    },
    {
      "name": "Steel Gray",
      "hex_code": "
                            
                            #4B4B4B
                        "
    },
    {
      "name": "Onyx",
      "hex_code": "
                            
                            #353535
                        "
    },
    {
      "name": "Shadow Gray",
      "hex_code": "
                            
                            #2C2C2C
                        "
    }
  ]
}

This palette consists of deeper shades of gray, perfect for creating an even more intense and moody dark theme. The colors provide a strong foundation that can enhance the overall atmosphere of your design.

Would you like to add any specific accent colors to this darker palette, or do you have other preferences in mind?