BuiltWith - Find out the technology behind websites
Sales List by Prospect.io - A curated list of tools & resources for salespeople
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.
Bumpsale - Sell your awesome digital product using incremental pricing