You can use the following example to remove all Likert fields from the form builder.

add_filter( 'frm_fields_in_form_builder', 'remove_likert_form_builder', 10, 2);
function remove_likert_form_builder( $fields, $args ) {
	if ( 13 != $args['form']->id ) {
		return $fields; // Do not modify fields if this is not the form you want.
	}

	// Remove all Likert fields.
	foreach ( $fields as $index => $field ) {
		$field = (object) $field;
		if ( 'likert' === $field->type ) {
			unset( $fields[ $index ] );
		}
	}
	return $fields;
}