Take an IP and try to look for the domain/host associated with it.
Get approximate IP details.
Get all possible details about an SSL certificate.
Get all possible details about a domain name.
Ping a website, server or port..
Validate JSON content and make it looks good.
Get details of any file type, such as the mime type or last edit date.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Check whether or not a website is using the new HTTP/2 protocol or not.