ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
LocationAPI - Instantly locate any device w/ WiFi, celltowers & IP address
ipapi - Web analytics with IP address lookup and location API
IPTrace - API to build location-aware mobile and web apps
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
Eyep - Coolest way to get your IP