Rescan.io - Find the technology stack behind any website. Get the lists of websites using any technology.

BuiltWith - Find out the technology behind websites

Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.

WebTechDB - WebTechDB provides raw access to their entire database of websites and their technologies. There's no download limits and it's updated daily.

CubDomain - CubDomain.com is the site to check website's statistics, Information, Whois Record, Hosting...

SalesOptimize - Selling to online retailers? Revolutionary sales lead generation search engine driven by deep web analytics