BuiltWith - Find out the technology behind websites
Paco - Never miss a thing on Slack — be more calm and productive
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Attentive - A marketing channel, built for retail & e‑commerce
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
UXPin + Slack - Keep tabs on design projects in Slack