Add scripts and links to the header
Be very careful when loading external JavaScript! You are essentially trusting the script provider with access to all the data available on the page. Unless you are 100% sure you trust the provider DO NOT add any external scripts to your application.
Custom fonts
Always keep in mind that adding additional assets to the page head will increase the page load time . While lots of tools might seem useful, they often come with a degraded user experience due to slower load times.