BuiltWith - Find out the technology behind websites
Kompyte - Track & analyze competitors in real time.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Akita - Software to help companies retain customers & grow revenue 💰
Similar Tech - SimilarTech offers a Sales Insights platform which helps companies uncover their ideal market by crawling the sourcecode of over 300M sites.