Brandpa - Domain names for startups
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
sub.dom.ain.studio - Search trillions of subdomains & get your perfect name
Whoisology - Connected database of whois records and whois history
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
WebCargo - Optimize your workflow by offloading it to us. Useful API's with seamless integration that scale to your needs.