List of free profiling stuff for developerππ½
If you're looking for all programming tools around profiling (not just free). Check this page List of profiling Programming Tools

Similarweb
Similarweb is the ultimate competitive digital intelligence tool for a complete 360-degree view of your industry, competitors, and customers.
Tag: profiling, information, research
1 user Limited access to historical data

Wappalyzer
Find out the technology stack of any website. Create lists of websites and contacts by the technologies they use.
Tag: profiling, information, research
1 User 50 credits/mo

whatruns
Discover what runs a website, a free browser extension that helps you identify technologies used on any website at the click of a button.
Tag: profiling, information, research

BuiltWith
Web technology information profiler tool. Find out what a website is built with.
Tag: profiling, information, research