My guess is that a postdoc would be seen by prospective employers as a clear declaration of intent to stay in academia. But if that is what you want, you should use those few (hopefully!) years to build up a research portfolio which will get you a permanent position. Starting from scratch on something which you have no previous experience with is not the way to do that. I doubt anybody sensible would be willing to let you try on their dime.
If you do not intend to stay in academia, it is time to start revising down the value you assign to certificates of whatever. You are more likely to be asked for an interesting GitHub repo. But if you insist, there is a plethora of things like
My guess is that a postdoc would be seen by prospective employers as a clear declaration of intent to stay in academia. But if that is what you want, you should use those few (hopefully!) years to build up a research portfolio which will get you a permanent position. Starting from scratch on something which you have no previous experience with is not the way to do that. I doubt anybody sensible would be willing to let you try on their dime.
If you do not intend to stay in academia, it is time to start revising down the value you assign to certificates of whatever. You are more likely to be asked for an interesting GitHub repo. But if you insist, there is a plethora of things like
https://www.microsoft.com/en-us/learning/certification-overv...
http://education.oracle.com/pls/web_prod-plq-dad/db_pages.ge...
https://training.linuxfoundation.org/certification