ResumeGo's resume scanner is definitely the best one I've come across online. It mimics ATS's which from my research, are used a lot by employers, so this has helped me learn a lot about whether my own resume is compatible with their algorithms.
I also ran across Jobscan's resume scanner and they were both super useful... I highly recommend people looking for jobs to see if their resumes can perform well when faced against applicant trackers by testing their resume on sites like the 2 I've come across.