IsHostedBy.com - IsHostedBy is a website where you can lookup where certain websites are hosted.

Whoisology - Connected database of whois records and whois history

CubDomain - CubDomain.com is the site to check website's statistics, Information, Whois Record, Hosting...

Bulk Whois API - Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, top notch support, and more.

Website Informer - Website.informer: complete data lookup & free aggregated report on any domain including whois, visitors, IP & DNS details, competitors, owners, etc

WhoisAPI - WhoisAPI is the premier provider of freshly parsed whois data for domain names and IP addresses...