DNSdumpster.com - Open source domain intelligence lookups for security recon
ipdata.co - Get the Geolocation, Organisation, Currency, Timezone, Calling Code, Flag, Proxy, Tor and Threat intelligence data from any IPv4 or IPv6 address.
ViewDNS.info - Free DNS related tools including Reverse IP Lookup, DNS Propagation Checker, Chinese Firewall Test...
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
DNS Checker Tool - Check Domain Name System (DNS) records for any website.
ipinfo.io - Simple IP address information.