IP2Location is an IP geolocation solution to identify country, region, city, latitude & longitude, ZIP code, time zone, connection speed, ISP, domain name, IDD country code, area code, weather station data, mobile network codes (MNC), mobile country codes (MCC), mobile carrier, elevation and usage type.
DNSdumpster.com - Open source domain intelligence lookups for security recon
ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
DomainTools - Domain name research, including comprehensive Whois Lookup, Reverse Whois Lookup and Whois History.
ipapi - Web analytics with IP address lookup and location API
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