WordPress loads oEmbed scripts for embedding content from YouTube, Twitter, etc. If you do not use embeds, remove them. For more performance tips, see the Guide to Google PageSpeed for WordPress.
remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );
remove_action( 'wp_head', 'wp_oembed_add_host_js' );
remove_action( 'rest_api_init', 'wp_oembed_register_route' );
add_filter( 'embed_oembed_discover', '__return_false' );
add_filter( 'oembed_dataparse', '__return_false' );