Multi Whois is a small whois domain name search program capable of finding bulk domains via a wordlist file or specific domains provided by the user. It's a good way to search for domains that are available to buy.
The wordlist format consists of a domain name per line with or without the .dot tld.. Examples below
google
yahoo
foobar
Note:Must select a tld from the dropdown box
or
google.com
yahoo.net
foobar.guru