/**
 * Dynamic Select List for Contact Form 7
 * @usage [select name taxonomy:{$taxonomy} ...]
 *
 * @param Array $tag
 *
 * @return Array $tag
 */
function dynamic_select_list( $tag ) {

    // Only run on select lists
    if( 'select' !== $tag['type'] ) {
        return $tag;
    } else if ( empty( $tag['options'] ) ) {
        return $tag;
    }

    $term_args = array();

    // Loop thorugh options to look for our custom options
    foreach( $tag['options'] as $option ) {

        $matches = explode( ':', $option );

        if( ! empty( $matches ) ) {

            switch( $matches[0] ) {

                case 'taxonomy':
                    $term_args['taxonomy'] = $matches[1];
                    break;

                case 'parent':
                    $term_args['parent'] = intval( $matches[1] );
                    break;

            }
        }

    }

    // Ensure we have a term arguments to work with
    if( empty( $term_args ) ) {
        return $tag;
    }

    // Merge dynamic arguments with static arguments
    $term_args = array_merge( $term_args, array(
        'hide_empty' => false,
    ) );

    $terms = get_terms( $term_args );

    // Add terms to values
    if( ! empty( $terms ) && ! is_wp_error( $term_args ) ) {

        foreach( $terms as $term ) {

            $tag['values'][] = $term->name;

        }

    }

    return $tag;

}
add_filter( 'wpcf7_form_tag', 'dynamic_select_list', 10 );

/** Dynamic List for Contact Form 7 **/
/** Usage: [select name term:taxonomy_name] **/
function dynamic_select_list($tag, $unused){
    $options = (array)$tag['options'];

    foreach ($options as $option)
        if (preg_match('%^term:([-0-9a-zA-Z_]+)$%', $option, $matches))
            $term = $matches[1];

    //check if post_type is set
    if(!isset($term))
        return $tag;

    $taxonomy = get_terms($term, array('hide_empty' => 0));

    if (!$taxonomy)
        return $tag;

    foreach ($taxonomy as $cat) {
        $tag['raw_values'][] = $cat->name;
        $tag['values'][] = $cat->name;
        $tag['labels'][] = $cat->name;
    }

    $tag['raw_values'][] = 'Other';
    $tag['values'][] = 'Other';
    $tag['labels'][] = 'Other - Please Specify Below';

    return $tag;
}
add_filter( 'wpcf7_form_tag', 'dynamic_select_list', 10, 2);