Here is a color palette based on your request for a full spectrum of 25% grey tinted colors, running the gamut across the hues in increments of five degrees from zero to 360.

json
{
  "palette_name": "25% Grey Tinted Spectrum",
  "colors": [
    { "name": "Red Tinted Grey", "hex_code": "
                            
                            #404040
                        " },
    { "name": "Red-Orange Tinted Grey", "hex_code": "
                            
                            #40403D
                        " },
    { "name": "Orange Tinted Grey", "hex_code": "
                            
                            #40403A
                        " },
    { "name": "Yellow-Orange Tinted Grey", "hex_code": "
                            
                            #404037
                        " },
    { "name": "Yellow Tinted Grey", "hex_code": "
                            
                            #404034
                        " },
    { "name": "Yellow-Green Tinted Grey", "hex_code": "
                            
                            #404031
                        " },
    { "name": "Green Tinted Grey", "hex_code": "
                            
                            #40402E
                        " },
    { "name": "Cyan-Green Tinted Grey", "hex_code": "
                            
                            #40402B
                        " },
    { "name": "Cyan Tinted Grey", "hex_code": "
                            
                            #404028
                        " },
    { "name": "Cyan-Blue Tinted Grey", "hex_code": "
                            
                            #404025
                        " },
    { "name": "Blue Tinted Grey", "hex_code": "
                            
                            #404022
                        " },
    { "name": "Blue-Purple Tinted Grey", "hex_code": "
                            
                            #40401F
                        " },
    { "name": "Purple Tinted Grey", "hex_code": "
                            
                            #40401C
                        " },
    { "name": "Purple-Red Tinted Grey", "hex_code": "
                            
                            #404019
                        " },
    { "name": "Red Tinted Grey", "hex_code": "
                            
                            #404016
                        " },
    { "name": "Red-Orange Tinted Grey", "hex_code": "
                            
                            #404013
                        " },
    { "name": "Orange Tinted Grey", "hex_code": "
                            
                            #404010
                        " },
    { "name": "Yellow-Orange Tinted Grey", "hex_code": "
                            
                            #40400D
                        " },
    { "name": "Yellow Tinted Grey", "hex_code": "
                            
                            #40400A
                        " },
    { "name": "Yellow-Green Tinted Grey", "hex_code": "
                            
                            #404007
                        " },
    { "name": "Green Tinted Grey", "hex_code": "
                            
                            #404004
                        " },
    { "name": "Cyan-Green Tinted Grey", "hex_code": "
                            
                            #404001
                        " },
    { "name": "Cyan Tinted Grey", "hex_code": "
                            
                            #404000
                        " },
    { "name": "Cyan-Blue Tinted Grey", "hex_code": "
                            
                            #4040FF
                        " },
    { "name": "Blue Tinted Grey", "hex_code": "
                            
                            #4040CC
                        " },
    { "name": "Blue-Purple Tinted Grey", "hex_code": "
                            
                            #404099
                        " },
    { "name": "Purple Tinted Grey", "hex_code": "
                            
                            #404066
                        " },
    { "name": "Purple-Red Tinted Grey", "hex_code": "
                            
                            #404033
                        " }
  ]
}

This palette showcases a range of colors tinted with 25% grey, providing a subtle and sophisticated appearance across the color wheel. Each color retains the essence of its hue while being slightly muted by the grey.

Would you like to explore any specific colors from this palette further or need assistance with anything else?