DiscoverOrg - DiscoverOrg is an IT sales intelligence platform providing technology marketers access to data, IT org charts, and real time projects.
ipstack - ipstack is a free, real-time IP address to location JSON API and database service supporting IPv4 and IPv6 lookup.
Clearbit - Clearbit provides Business Intelligence APIs
ipapi - Web analytics with IP address lookup and location API
LinkedIn Sales Navigator - Sales tool for LinkedIn users.
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database