Profile Hopper - Chrome Extension to Growth Hack LinkedIn
BuiltWith - Find out the technology behind websites
Sheety - Turn any Google sheet into an API instantly, for free. Power websites, apps, or whatever you like, all from a spreadsheet. Changes to your spreadsheet update your API in realtime. Neat
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Sheetsu - Turn Google Spreadsheet into API
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.