How to ‘clone’ select metabox options with a callback function? [closed]

Add a simple function in your functions.php file.

function get_button_styles(){
    return array(
        'button'         => 'Button',
        'button_red'     => 'Button Red',
        'button_yellow'  => 'Button Yellow',

    );
}

Use it to get button styles in different metabox fields

array(
    'id'    => 'all_btns',
    'name'  => 'Button Select',
    'type'  => 'select',
    'options' => get_button_styles(),             
    'callback' => 'metabox_clone_options',
),