ipdata.co - Get the Geolocation, Organisation, Currency, Timezone, Calling Code, Flag, Proxy, Tor and Threat intelligence data from any IPv4 or IPv6 address.
DomainTools - Domain name research, including comprehensive Whois Lookup, Reverse Whois Lookup and Whois History.
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
APISpot.io - Bulk WHOIS and Domain Names API on steroids, Parsed and in JSON, Domain Availability Check, Domain and WHOIS Lookup
ipinfo.io - Simple IP address information.
Domain Details - Displays Server Type, Headers, IP Address, Location Flag, and links to Whois Reports.