Make sure your passwords are good enough.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Convert text to ascii and the other way for any string input.
Easily convert bits (bit) to yobibits (Yibit).
Get all possible details about a domain name.
Take an IP and try to look for the domain/host associated with it.
Get approximate IP details.