Get approximate IP details.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get all possible details about an SSL certificate.
Get all possible details about a domain name.
Ping a website, server or port..
Easily convert IDN to Punnycode and back.
Extract email addresses from any kind of text content.
Make sure your passwords are good enough.
Check for 301 & 302 redirects of a specific URL. It will check for up to 10 redirects.
Take an IP and try to look for the domain/host associated with it.