ipinfo.io - Simple IP address information.
IP-API.com - Free IP Geolocation API - lookup any IP address
IPTools - The "IP Tools" is powerful and handy application for network analyzing.
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
ipapi - Web analytics with IP address lookup and location API