get_special_noptin_form_fields()

function get_special_noptin_form_fields() {

	// array of fields.
	$fields = array();

	// Retrieve subscription forms.
	$forms = get_posts(
		array(
        	'numberposts' => -1,
        	'post_status' => array( 'draft', 'publish' ),
        	'post_type'   => 'noptin-form',
        	'fields'      => 'ids',
		)
	);

	// Ignore some fields.
	$to_ignore = array(
        'email',
        'first_name',
        'last_name',
        'name',
        'GDPR_consent'
	);
	$to_ignore = apply_filters( 'noptin_special_fields_to_ignore', $to_ignore );

	foreach ( $forms as $form ) {

        // Retrieve state.
        $state = get_post_meta( $form, '_noptin_state', true );
		if ( ! is_array( $state ) ) {
			continue;
        }

        if ( empty( $state['fields'] ) ||  ! is_array( $state['fields'] ) ) {
			continue;
        }

        foreach ( $state['fields'] as $field ) {
            $name  = $field['type']['name'];
            $type  = $field['type']['type'];
            $label = $field['type']['label'];

            if ( in_array( $name, $to_ignore, true ) || in_array( $type, $to_ignore, true ) ) {
                continue;
            }

            if ( 'text' !== $name && 'checkbox' !== $type ) {
                $label = $name;
            }

            $fields[ $name ] = array(
                $type,
                $label
            );
        }

    }

	return apply_filters( 'special_noptin_form_fields', $fields );
}