BuiltWith - Find out the technology behind websites
hubsell - Sales automation for modern sales teams
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Elucify - A completely free software tool that uses crowdsourced data to find business email addresses
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Nexsales - B2B Demand Generation