Based on our record, UX Metrics seems to be more popular. It has been mentiond 2 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
For free card sorting and tree testing (I didn't test that one personally though): https://uxmetrics.com/. Source: over 1 year ago
In case someone reads this in search of another tool, I did a search again, and found one I had missed, that actually has a usable free tier as of writing https://uxmetrics.com. - Source: Hacker News / almost 2 years ago
UserTesting.com - Usability testing has never been easier. Get videos of real people speaking their thoughts as they use websites, mobile apps, prototypes and more!
Sesov - A community for anonymous design feedback
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
Webabstract - UX Design Agency - We design products that people
UXtweak - Online user testing and usability platform
Optimal Workshop - A User Research Platform that helps you and your team make design decisions with confidence.