Encode any string input to Base64.
Get the gravatar.com globally recognized avatar for any email.
Make sure your passwords are good enough.
Check if the URL is banned and marked as safe/unsafe by Google.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Take an IP and try to look for the domain/host associated with it.
Get details of any file type, such as the mime type or last edit date.