Open function.php and add this code:

// change counts at blog pages
add_filter('widget_tag_cloud_args', 'tag_widget_limit'); 
function tag_widget_limit($args){
 if(isset($args['taxonomy']) && $args['taxonomy'] == 'post_tag'){
  $args['number'] = 300; //Limit number of tags
 }
 return $args;
}

// change counts in Woocomerce
function custom_woocommerce_tag_cloud_widget() {
    $args = array(
        'number' => 500,
        'taxonomy' => 'product_tag'
    );
    return $args;
}
add_filter( 'woocommerce_product_tag_cloud_widget_args', 'custom_woocommerce_tag_cloud_widget' );