Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
WhatRuns - Extension that helps you identify technologies used on any website at the click of a button.
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.
Albacross - The world's first free B2B Lead Generation Network. Albacross help companies master their B2B digital marketing with Lead Generation and targeted marketing
Whoisology - Connected database of whois records and whois history