ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
Near - Near is a Location-aware Data Platform that helps you Unify & Enrich your data, Take action and Measure Results.
ipapi - Web analytics with IP address lookup and location API
ipinfo.io - Simple IP address information.
geoPlugin - geoPlugin is a free and easy webmaster resource that provides geolocation technology.
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database