IP Guide - Look up IP addresses, networks, and ASNs
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
IPconfig.pw - The best tool to view information about IP addresses
Bulk Whois API - Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, top notch support, and more.
ipXapi - The most complete IP to geolocation API.
Whoisology - Connected database of whois records and whois history