Whatsmyserp - Powerful Rank & Serp Tracking. Completely Free.
Postman - The Collaboration Platform for API Development
SEOmator - SEO website analysis & audit tool
Sauce Labs - Test mobile or web apps instantly across 700+ browser/OS/device platform combinations - without infrastructure setup.
Panguin Tool by Barracuda Digital - See your website's Google organic visit data overlaid with Google's major algorithm updates and changes to easily identify the impact on your website. Technology by Barracuda Digital.
TestComplete - TestComplete Desktop, Web, and Mobile helps you create repeatable and accurate automated tests across multiple devices, platforms, and environments easily and quickly.