GMass - GMass allows you to easily schedule emails, send out mass emails and mail merge campaigns and more with Gmail! Click here to learn about more features!
BuiltWith - Find out the technology behind websites
Elevatr Email Marketing Automation - Fast and easy email marketing software
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Google Sheets Email Marketing - Email automation and validations directly from Google Sheets
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.