Take an IP and try to look for the domain/host associated with it.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get approximate IP details.
Get all possible details about an SSL certificate.
Ping a website, server or port..
Get the gravatar.com globally recognized avatar for any email.
Decode Base64 input to back to string.
Convert text to ascii and the other way for any string input.
Encode any string input to Base64.
Make sure your passwords are good enough.
Decode Base64 input to an image.