The ones recruiters search for
A free certificate earns its place when hiring managers already know the issuer from their own work. That is a much shorter list than the number of platforms handing out PDFs.
In marketing, Google's digital marketing fundamentals and HubSpot's inbound and SEO certifications appear regularly in job adverts. In infrastructure and security, Cisco's introductory networking and security courses are recognised because colleges have taught them for two decades. In development, freeCodeCamp's certifications carry weight mostly because each one requires five working projects.
Why the issuer matters more than the content
A certificate is a signal, and a signal only works if the receiver can decode it. A hiring manager who runs Google Ads every day knows exactly what the Google certification covers. The same manager has never heard of most platform-branded credentials and will treat them as noise.
This is why an audit-only course from MIT can be worth more on a CV than a certificated course from an unknown provider — provided you can talk about what you built with it.
What to do with the rest
Take them for the knowledge, list them in a single 'Continuing education' line rather than as separate achievements, and put the effort into projects instead. Nobody has ever been hired for the length of their certificate list.