BuiltWith - Find out the technology behind websites
Salesforce Data.com - Data.com provides company profiles and contact information across millions of businesses worldwide.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
FullContact - Put the power of full contact information into your web or mobile apps.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Demografy - Demografy is a SaaS platform that uses AI to predict customer demographics from names. It provides full coverage, accuracy estimate before purchase and work with even masked names enabling privacy and GDPR-compliance.