Prospect Stack - 100 ways to generate more prospects
BuiltWith - Find out the technology behind websites
Bumpsale - Sell your awesome digital product using incremental pricing
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Mailshake Omni - Sales engagement software for modern sales teams
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.