Single properties - Colors
The format hexcolor is used to display a color picker, you can also use the x-display=color-picker annotation. If using the format syntax, please note that hexcolor is not a standard format (I'm pretty sure it was once a proposal) and you might need to declare it with your JSON schema validator.
Example ajv format: ajv.addFormat('hexcolor', /^#[0-9A-Fa-f]{6,8}$/)
You can customize the color picker using either the colorPickerProps option or the x-props annotation.