BuiltWith - Find out the technology behind websites
Pingboard - Pingboard is the employee experience suite for growing companies that put their people first.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Organimi - It's more than an org chart.