ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
Radar - Radar - Location sharing for friends and teams.
ipapi - Web analytics with IP address lookup and location API
HyperTrack - Build logistics apps that feel like the future
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
LocationAPI - Instantly locate any device w/ WiFi, celltowers & IP address