Get all possible details about an SSL certificate.
Get all the HTTP headers that an URL returns for a typical GET request.
Check whether a website is using the new HTTP/2 protocol or not.
Upload a QR code image and extract the data out of it.
Make sure your passwords are good enough.
Get approximate IP details.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Parse details from any URLs.